21929900 has 36 divisors (see below), whose sum is σ = 48882288. Its totient is φ = 8533440.

The previous prime is 21929893. The next prime is 21929903. The reversal of 21929900 is 992912.

It is not an unprimeable number, because it can be changed into a prime (21929903) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 737 + ... + 6663.

Almost surely, 2^21929900 is an apocalyptic number.

21929900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21929900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24441144).

21929900 is an abundant number, since it is smaller than the sum of its proper divisors (26952388).

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

21929900 is a wasteful number, since it uses less digits than its factorization.

21929900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5978 (or 5971 counting only the distinct ones).

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 21929900 is about 4682.9371125395. The cubic root of 21929900 is about 279.9060058653.

The spelling of 21929900 in words is "twenty-one million, nine hundred twenty-nine thousand, nine hundred".