261401872 has 10 divisors (see below), whose sum is σ = 506466158. Its totient is φ = 130700928.

The previous prime is 261401869. The next prime is 261401879. The reversal of 261401872 is 278104162.

It can be written as a sum of positive squares in only one way, i.e., 241367296 + 20034576 = 15536^2 + 4476^2 .

It is not an unprimeable number, because it can be changed into a prime (261401879) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8168793 + ... + 8168824.

Almost surely, 2^261401872 is an apocalyptic number.

It is an amenable number.

261401872 is a deficient number, since it is larger than the sum of its proper divisors (245064286).

261401872 is a wasteful number, since it uses less digits than its factorization.

261401872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16337625 (or 16337619 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 261401872 is about 16167.9272635672. The cubic root of 261401872 is about 639.3954838677.

The spelling of 261401872 in words is "two hundred sixty-one million, four hundred one thousand, eight hundred seventy-two".