261190638 has 24 divisors (see below), whose sum is σ = 571206168. Its totient is φ = 86249232.

The previous prime is 261190619. The next prime is 261190649. The reversal of 261190638 is 836091162.

261190638 is a `hidden beast` number, since 2 + 6 + 1 + 19 + 0 + 638 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 65881 + ... + 69732.

It is an arithmetic number, because the mean of its divisors is an integer number (23800257).

Almost surely, 2^261190638 is an apocalyptic number.

261190638 is an abundant number, since it is smaller than the sum of its proper divisors (310015530).

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

261190638 is a wasteful number, since it uses less digits than its factorization.

261190638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135728 (or 135725 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 261190638 is about 16161.3934423985. The cubic root of 261190638 is about 639.2232095819.

The spelling of 261190638 in words is "two hundred sixty-one million, one hundred ninety thousand, six hundred thirty-eight".