215566721616 has 20 divisors (see below), whose sum is σ = 556880697632. Its totient is φ = 71855573856.

The previous prime is 215566721581. The next prime is 215566721627. The reversal of 215566721616 is 616127665512.

215566721616 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×215566721616² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48), and also a Moran number because the ratio is a prime number: 4490973367 = 215566721616 / (2 + 1 + 5 + 5 + 6 + 6 + 7 + 2 + 1 + 6 + 1 + 6).

It is a congruent number.

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, 2245486636 + ... + 2245486731.

Almost surely, 2^215566721616 is an apocalyptic number.

It is an amenable number.

215566721616 is an abundant number, since it is smaller than the sum of its proper divisors (341313976016).

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

215566721616 is a wasteful number, since it uses less digits than its factorization.

215566721616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4490973378 (or 4490973372 counting only the distinct ones).

The product of its digits is 907200, while the sum is 48.

The spelling of 215566721616 in words is "two hundred fifteen billion, five hundred sixty-six million, seven hundred twenty-one thousand, six hundred sixteen".