21621845115 has 24 divisors (see below), whose sum is σ = 40360778640. Its totient is φ = 10644600384.

The previous prime is 21621845099. The next prime is 21621845117. The reversal of 21621845115 is 51154812612.

21621845115 is a `hidden beast` number, since 2 + 1 + 62 + 1 + 84 + 511 + 5 = 666.

It is not a de Polignac number, because 21621845115 - 2⁴ = 21621845099 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21621845115.

It is not an unprimeable number, because it can be changed into a prime (21621845117) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18479625 + ... + 18480794.

It is an arithmetic number, because the mean of its divisors is an integer number (1681699110).

Almost surely, 2^21621845115 is an apocalyptic number.

21621845115 is a deficient number, since it is larger than the sum of its proper divisors (18738933525).

21621845115 is a wasteful number, since it uses less digits than its factorization.

21621845115 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36960443 (or 36960440 counting only the distinct ones).

The product of its digits is 19200, while the sum is 36.

The spelling of 21621845115 in words is "twenty-one billion, six hundred twenty-one million, eight hundred forty-five thousand, one hundred fifteen".