21522858 has 48 divisors (see below), whose sum is σ = 52722720. Its totient is φ = 5824224.

The previous prime is 21522829. The next prime is 21522859. The reversal of 21522858 is 85822512.

It is not an unprimeable number, because it can be changed into a prime (21522859) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3660 + ... + 7512.

It is an arithmetic number, because the mean of its divisors is an integer number (1098390).

Almost surely, 2^21522858 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21522858, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26361360).

21522858 is an abundant number, since it is smaller than the sum of its proper divisors (31199862).

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

21522858 is a wasteful number, since it uses less digits than its factorization.

21522858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3891 (or 3884 counting only the distinct ones).

The product of its digits is 12800, while the sum is 33.

The square root of 21522858 is about 4639.2734344938. The cubic root of 21522858 is about 278.1633961719.

The spelling of 21522858 in words is "twenty-one million, five hundred twenty-two thousand, eight hundred fifty-eight".