261977856 has 72 divisors (see below), whose sum is σ = 796865664. Its totient is φ = 74849280.

The previous prime is 261977791. The next prime is 261977867. The reversal of 261977856 is 658779162.

It is a junction number, because it is equal to n+sod(n) for n = 261977799 and 261977808.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18990 + ... + 29741.

Almost surely, 2^261977856 is an apocalyptic number.

It is an amenable number.

261977856 is an abundant number, since it is smaller than the sum of its proper divisors (534887808).

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

261977856 is an equidigital number, since it uses as much as digits as its factorization.

261977856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48757 (or 48743 counting only the distinct ones).

The product of its digits is 1270080, while the sum is 51.

The square root of 261977856 is about 16185.7300113402. The cubic root of 261977856 is about 639.8647630921.

The spelling of 261977856 in words is "two hundred sixty-one million, nine hundred seventy-seven thousand, eight hundred fifty-six".