261644040 has 256 divisors, whose sum is σ = 1017100800. Its totient is φ = 58586112.

The previous prime is 261644029. The next prime is 261644051. The reversal of 261644040 is 40446162.

261644040 is a `hidden beast` number, since 2 + 616 + 4 + 4 + 0 + 40 = 666.

261644040 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (261644029) and next prime (261644051).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 261643995 and 261644013.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 400354 + ... + 401006.

It is an arithmetic number, because the mean of its divisors is an integer number (3973050).

Almost surely, 2^261644040 is an apocalyptic number.

261644040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261644040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (508550400).

261644040 is an abundant number, since it is smaller than the sum of its proper divisors (755456760).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261644040 is a wasteful number, since it uses less digits than its factorization.

261644040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 733 (or 723 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

The square root of 261644040 is about 16175.4146778375. The cubic root of 261644040 is about 639.5928725767.

It can be divided in two parts, 2616 and 44040, that added together give a 6-th power (46656 = 6⁶).

The spelling of 261644040 in words is "two hundred sixty-one million, six hundred forty-four thousand, forty".