261159864 has 64 divisors (see below), whose sum is σ = 785452800. Its totient is φ = 70689024.

The previous prime is 261159853. The next prime is 261159881. The reversal of 261159864 is 468951162.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37717 + ... + 44100.

It is an arithmetic number, because the mean of its divisors is an integer number (12272700).

Almost surely, 2^261159864 is an apocalyptic number.

261159864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

261159864 is an abundant number, since it is smaller than the sum of its proper divisors (524292936).

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

261159864 is a wasteful number, since it uses less digits than its factorization.

261159864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81852 (or 81848 counting only the distinct ones).

The product of its digits is 103680, while the sum is 42.

The square root of 261159864 is about 16160.4413306073. The cubic root of 261159864 is about 639.1981037463.

The spelling of 261159864 in words is "two hundred sixty-one million, one hundred fifty-nine thousand, eight hundred sixty-four".