21974920 has 32 divisors (see below), whose sum is σ = 53939520. Its totient is φ = 7990720.

The previous prime is 21974917. The next prime is 21974921. The reversal of 21974920 is 2947912.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21974921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24532 + ... + 25411.

It is an arithmetic number, because the mean of its divisors is an integer number (1685610).

Almost surely, 2^21974920 is an apocalyptic number.

21974920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21974920 is an abundant number, since it is smaller than the sum of its proper divisors (31964600).

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

21974920 is a wasteful number, since it uses less digits than its factorization.

21974920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49965 (or 49961 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 21974920 is about 4687.7414604477. The cubic root of 21974920 is about 280.0974150839.

It can be divided in two parts, 2197 and 4920, that added together give a palindrome (7117).

The spelling of 21974920 in words is "twenty-one million, nine hundred seventy-four thousand, nine hundred twenty".