21929620 has 12 divisors (see below), whose sum is σ = 46052244. Its totient is φ = 8771840.

The previous prime is 21929599. The next prime is 21929623. The reversal of 21929620 is 2692912.

It can be written as a sum of positive squares in 2 ways, for example, as 12082576 + 9847044 = 3476^2 + 3138^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21929623) 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 3 ways as a sum of consecutive naturals, for example, 548221 + ... + 548260.

It is an arithmetic number, because the mean of its divisors is an integer number (3837687).

Almost surely, 2^21929620 is an apocalyptic number.

21929620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21929620 is an abundant number, since it is smaller than the sum of its proper divisors (24122624).

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

21929620 is a wasteful number, since it uses less digits than its factorization.

21929620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1096490 (or 1096488 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 21929620 is about 4682.9072166764. The cubic root of 21929620 is about 279.9048145844.

The spelling of 21929620 in words is "twenty-one million, nine hundred twenty-nine thousand, six hundred twenty".