215686688651 has 4 divisors (see below), whose sum is σ = 246499072752. Its totient is φ = 184874304552.

The previous prime is 215686688621. The next prime is 215686688687. The reversal of 215686688651 is 156886686512.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 215686688651 - 2⁶ = 215686688587 is a prime.

It is a super-2 number, since 2×215686688651² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215686688611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15406192040 + ... + 15406192053.

It is an arithmetic number, because the mean of its divisors is an integer number (61624768188).

Almost surely, 2^215686688651 is an apocalyptic number.

215686688651 is a deficient number, since it is larger than the sum of its proper divisors (30812384101).

215686688651 is an equidigital number, since it uses as much as digits as its factorization.

215686688651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30812384100.

The product of its digits is 33177600, while the sum is 62.

The spelling of 215686688651 in words is "two hundred fifteen billion, six hundred eighty-six million, six hundred eighty-eight thousand, six hundred fifty-one".