21216521030 has 32 divisors (see below), whose sum is σ = 38341885248. Its totient is φ = 8452864000.

The previous prime is 21216521021. The next prime is 21216521041. The reversal of 21216521030 is 3012561212.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21216520987 and 21216521005.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2975870 + ... + 2982990.

It is an arithmetic number, because the mean of its divisors is an integer number (1198183914).

Almost surely, 2^21216521030 is an apocalyptic number.

21216521030 is a deficient number, since it is larger than the sum of its proper divisors (17125364218).

21216521030 is a wasteful number, since it uses less digits than its factorization.

21216521030 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8272.

The product of its (nonzero) digits is 720, while the sum is 23.

The spelling of 21216521030 in words is "twenty-one billion, two hundred sixteen million, five hundred twenty-one thousand, thirty".