21399300 has 216 divisors, whose sum is σ = 75828480. Its totient is φ = 5011200.

The previous prime is 21399299. The next prime is 21399307. The reversal of 21399300 is 399312.

It is not an unprimeable number, because it can be changed into a prime (21399307) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 362671 + ... + 362729.

Almost surely, 2^21399300 is an apocalyptic number.

21399300 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 21399300, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37914240).

21399300 is an abundant number, since it is smaller than the sum of its proper divisors (54429180).

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

21399300 is a wasteful number, since it uses less digits than its factorization.

21399300 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123 (or 113 counting only the distinct ones).

The product of its (nonzero) digits is 1458, while the sum is 27.

The square root of 21399300 is about 4625.9377427717. The cubic root of 21399300 is about 277.6300826693.

The spelling of 21399300 in words is "twenty-one million, three hundred ninety-nine thousand, three hundred".