261656620 has 24 divisors (see below), whose sum is σ = 550555488. Its totient is φ = 104457600.

The previous prime is 261656599. The next prime is 261656663. The reversal of 261656620 is 26656162.

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, 2136 + ... + 22975.

It is an arithmetic number, because the mean of its divisors is an integer number (22939812).

Almost surely, 2^261656620 is an apocalyptic number.

261656620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261656620 is an abundant number, since it is smaller than the sum of its proper divisors (288898868).

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

261656620 is a wasteful number, since it uses less digits than its factorization.

261656620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25641 (or 25639 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 261656620 is about 16175.8035349098. The cubic root of 261656620 is about 639.6031230801.

The spelling of 261656620 in words is "two hundred sixty-one million, six hundred fifty-six thousand, six hundred twenty".