261220656 has 20 divisors (see below), whose sum is σ = 674820152. Its totient is φ = 87073536.

The previous prime is 261220627. The next prime is 261220693. The reversal of 261220656 is 656022162.

261220656 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×261220656² = 136472462242140672, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2721001 + ... + 2721096.

Almost surely, 2^261220656 is an apocalyptic number.

It is an amenable number.

261220656 is an abundant number, since it is smaller than the sum of its proper divisors (413599496).

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

261220656 is a wasteful number, since it uses less digits than its factorization.

261220656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5442108 (or 5442102 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 261220656 is about 16162.3221103900. The cubic root of 261220656 is about 639.2476967629.

The spelling of 261220656 in words is "two hundred sixty-one million, two hundred twenty thousand, six hundred fifty-six".