261123640 has 16 divisors (see below), whose sum is σ = 587528280. Its totient is φ = 104449440.

The previous prime is 261123619. The next prime is 261123647. The reversal of 261123640 is 46321162.

261123640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261123647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3264006 + ... + 3264085.

Almost surely, 2^261123640 is an apocalyptic number.

261123640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261123640 is an abundant number, since it is smaller than the sum of its proper divisors (326404640).

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

261123640 is a wasteful number, since it uses less digits than its factorization.

261123640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6528102 (or 6528098 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 261123640 is about 16159.3205302698. The cubic root of 261123640 is about 639.1685492015.

The spelling of 261123640 in words is "two hundred sixty-one million, one hundred twenty-three thousand, six hundred forty".