261554634 has 24 divisors (see below), whose sum is σ = 618220512. Its totient is φ = 79258920.

The previous prime is 261554633. The next prime is 261554651. The reversal of 261554634 is 436455162.

261554634 is a `hidden beast` number, since 2 + 6 + 15 + 5 + 4 + 634 = 666.

261554634 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (261554633) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 660294 + ... + 660689.

It is an arithmetic number, because the mean of its divisors is an integer number (25759188).

Almost surely, 2^261554634 is an apocalyptic number.

261554634 is an abundant number, since it is smaller than the sum of its proper divisors (356665878).

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

261554634 is a wasteful number, since it uses less digits than its factorization.

261554634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1321002 (or 1320999 counting only the distinct ones).

The product of its digits is 86400, while the sum is 36.

The square root of 261554634 is about 16172.6508031306. The cubic root of 261554634 is about 639.5200128306.

The spelling of 261554634 in words is "two hundred sixty-one million, five hundred fifty-four thousand, six hundred thirty-four".