261877864 has 16 divisors (see below), whose sum is σ = 497748420. Its totient is φ = 129144960.

The previous prime is 261877853. The next prime is 261877867. The reversal of 261877864 is 468778162.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 253128100 + 8749764 = 15910^2 + 2958^2 .

It is not an unprimeable number, because it can be changed into a prime (261877867) 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, 223627 + ... + 224794.

Almost surely, 2^261877864 is an apocalyptic number.

It is an amenable number.

261877864 is a deficient number, since it is larger than the sum of its proper divisors (235870556).

261877864 is a wasteful number, since it uses less digits than its factorization.

261877864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448500 (or 448496 counting only the distinct ones).

The product of its digits is 903168, while the sum is 49.

The square root of 261877864 is about 16182.6408228076. The cubic root of 261877864 is about 639.7833446340.

The spelling of 261877864 in words is "two hundred sixty-one million, eight hundred seventy-seven thousand, eight hundred sixty-four".