21022156 has 12 divisors (see below), whose sum is σ = 37202760. Its totient is φ = 10392800.

The previous prime is 21022117. The next prime is 21022163. The reversal of 21022156 is 65122012.

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, 29170 + ... + 29881.

It is an arithmetic number, because the mean of its divisors is an integer number (3100230).

Almost surely, 2^21022156 is an apocalyptic number.

It is an amenable number.

21022156 is a deficient number, since it is larger than the sum of its proper divisors (16180604).

21022156 is a wasteful number, since it uses less digits than its factorization.

21022156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59144 (or 59142 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 21022156 is about 4584.9924754573. The cubic root of 21022156 is about 275.9894100817.

Adding to 21022156 its reverse (65122012), we get a palindrome (86144168).

It can be divided in two parts, 210 and 22156, that added together give a triangular number (22366 = T₂₁₁).

The spelling of 21022156 in words is "twenty-one million, twenty-two thousand, one hundred fifty-six".