21396900 has 144 divisors (see below), whose sum is σ = 73995264. Its totient is φ = 4667520.

The previous prime is 21396899. The next prime is 21396901. The reversal of 21396900 is 969312.

21396900 = 259² + 260² + ... + 433².

It is an interprime number because it is at equal distance from previous prime (21396899) and next prime (21396901).

It is a super-2 number, since 2×21396900² = 915654659220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (21396901) 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 47 ways as a sum of consecutive naturals, for example, 48079 + ... + 48521.

It is an arithmetic number, because the mean of its divisors is an integer number (513856).

Almost surely, 2^21396900 is an apocalyptic number.

21396900 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 21396900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36997632).

21396900 is an abundant number, since it is smaller than the sum of its proper divisors (52598364).

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

21396900 is a wasteful number, since it uses less digits than its factorization.

21396900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 490 (or 483 counting only the distinct ones).

The product of its (nonzero) digits is 2916, while the sum is 30.

The square root of 21396900 is about 4625.6783286346. The cubic root of 21396900 is about 277.6197032470.

The spelling of 21396900 in words is "twenty-one million, three hundred ninety-six thousand, nine hundred".