21906984 has 32 divisors (see below), whose sum is σ = 59747040. Its totient is φ = 6638400.

The previous prime is 21906961. The next prime is 21907007. The reversal of 21906984 is 48960912.

It is an interprime number because it is at equal distance from previous prime (21906961) and next prime (21907007).

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41227 + ... + 41754.

It is an arithmetic number, because the mean of its divisors is an integer number (1867095).

Almost surely, 2^21906984 is an apocalyptic number.

21906984 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21906984 is an abundant number, since it is smaller than the sum of its proper divisors (37840056).

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

21906984 is a wasteful number, since it uses less digits than its factorization.

21906984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83001 (or 82997 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 39.

The square root of 21906984 is about 4680.4897179676. The cubic root of 21906984 is about 279.8084744648.

The spelling of 21906984 in words is "twenty-one million, nine hundred six thousand, nine hundred eighty-four".