261222656 has 18 divisors (see below), whose sum is σ = 521425422. Its totient is φ = 130611200.

The previous prime is 261222653. The next prime is 261222713. The reversal of 261222656 is 656222162.

It can be written as a sum of positive squares in only one way, i.e., 248377600 + 12845056 = 15760^2 + 3584^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (261222653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 509945 + ... + 510456.

It is an arithmetic number, because the mean of its divisors is an integer number (28968079).

Almost surely, 2^261222656 is an apocalyptic number.

It is an amenable number.

261222656 is a deficient number, since it is larger than the sum of its proper divisors (260202766).

261222656 is an equidigital number, since it uses as much as digits as its factorization.

261222656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1020417 (or 1020403 counting only the distinct ones).

The product of its digits is 17280, while the sum is 32.

The square root of 261222656 is about 16162.3839825689. The cubic root of 261222656 is about 639.2493281961.

The spelling of 261222656 in words is "two hundred sixty-one million, two hundred twenty-two thousand, six hundred fifty-six".