21816038016 has 128 divisors (see below), whose sum is σ = 67187318400. Its totient is φ = 6955812864.

The previous prime is 21816037981. The next prime is 21816038033. The reversal of 21816038016 is 61083061812.

21816038016 is a `hidden beast` number, since 218 + 1 + 60 + 380 + 1 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 57741 + ... + 216716.

It is an arithmetic number, because the mean of its divisors is an integer number (524900925).

Almost surely, 2^21816038016 is an apocalyptic number.

It is an amenable number.

21816038016 is an abundant number, since it is smaller than the sum of its proper divisors (45371280384).

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

21816038016 is a wasteful number, since it uses less digits than its factorization.

21816038016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274503 (or 274485 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

Adding to 21816038016 its reverse (61083061812), we get a palindrome (82899099828).

The spelling of 21816038016 in words is "twenty-one billion, eight hundred sixteen million, thirty-eight thousand, sixteen".