261025740 has 84 divisors (see below), whose sum is σ = 821901024. Its totient is φ = 69602976.

The previous prime is 261025729. The next prime is 261025741. The reversal of 261025740 is 47520162.

261025740 is a `hidden beast` number, since 2 + 610 + 2 + 5 + 7 + 40 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (261025741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 5629 + ... + 23531.

It is an arithmetic number, because the mean of its divisors is an integer number (9784536).

Almost surely, 2^261025740 is an apocalyptic number.

261025740 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 261025740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (410950512).

261025740 is an abundant number, since it is smaller than the sum of its proper divisors (560875284).

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

261025740 is a wasteful number, since it uses less digits than its factorization.

261025740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17930 (or 17913 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 261025740 is about 16156.2910347641. The cubic root of 261025740 is about 639.0886605802.

The spelling of 261025740 in words is "two hundred sixty-one million, twenty-five thousand, seven hundred forty".