656666655 has 8 divisors (see below), whose sum is σ = 1050666672. Its totient is φ = 350222208.

The previous prime is 656666603. The next prime is 656666669. The reversal of 656666655 is 556666656.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 656666655 - 2¹³ = 656658463 is a prime.

It is a super-2 number, since 2×656666655² = 862422191577778050, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 656666598 and 656666607.

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, 21888874 + ... + 21888903.

It is an arithmetic number, because the mean of its divisors is an integer number (131333334).

Almost surely, 2^656666655 is an apocalyptic number.

656666655 is a deficient number, since it is larger than the sum of its proper divisors (394000017).

656666655 is a wasteful number, since it uses less digits than its factorization.

656666655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43777785.

The product of its digits is 5832000, while the sum is 51.

The square root of 656666655 is about 25625.5078974057. The cubic root of 656666655 is about 869.1905339174.

Subtracting from 656666655 its reverse (556666656), we obtain a palindrome (99999999).

The spelling of 656666655 in words is "six hundred fifty-six million, six hundred sixty-six thousand, six hundred fifty-five".