21217038 has 16 divisors (see below), whose sum is σ = 43897680. Its totient is φ = 6828416.

The previous prime is 21217033. The next prime is 21217039. The reversal of 21217038 is 83071212.

It is a junction number, because it is equal to n+sod(n) for n = 21216999 and 21217017.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21217033) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60795 + ... + 61142.

It is an arithmetic number, because the mean of its divisors is an integer number (2743605).

Almost surely, 2^21217038 is an apocalyptic number.

21217038 is an abundant number, since it is smaller than the sum of its proper divisors (22680642).

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

21217038 is a wasteful number, since it uses less digits than its factorization.

21217038 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121971.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 21217038 is about 4606.1956102623. The cubic root of 21217038 is about 276.8396244381.

The spelling of 21217038 in words is "twenty-one million, two hundred seventeen thousand, thirty-eight".