21394900 has 18 divisors (see below), whose sum is σ = 46427150. Its totient is φ = 8557920.

The previous prime is 21394897. The next prime is 21394903. The reversal of 21394900 is 949312.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21394897) and next prime (21394903).

It can be written as a sum of positive squares in 3 ways, for example, as 3400336 + 17994564 = 1844^2 + 4242^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21394903) 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 5 ways as a sum of consecutive naturals, for example, 106875 + ... + 107074.

Almost surely, 2^21394900 is an apocalyptic number.

21394900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21394900 is an abundant number, since it is smaller than the sum of its proper divisors (25032250).

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

21394900 is a wasteful number, since it uses less digits than its factorization.

21394900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213963 (or 213956 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 21394900 is about 4625.4621390732. The cubic root of 21394900 is about 277.6110531356.

The spelling of 21394900 in words is "twenty-one million, three hundred ninety-four thousand, nine hundred".