21913000 has 64 divisors (see below), whose sum is σ = 54334800. Its totient is φ = 8243200.

The previous prime is 21912977. The next prime is 21913037. The reversal of 21913000 is 31912.

It can be written as a sum of positive squares in 8 ways, for example, as 4955076 + 16957924 = 2226^2 + 4118^2 .

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 16356 + ... + 17644.

Almost surely, 2^21913000 is an apocalyptic number.

21913000 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 21913000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27167400).

21913000 is an abundant number, since it is smaller than the sum of its proper divisors (32421800).

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

21913000 is a wasteful number, since it uses less digits than its factorization.

21913000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1327 (or 1313 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 16.

The square root of 21913000 is about 4681.1323416456. The cubic root of 21913000 is about 279.8340853798.

Adding to 21913000 its reverse (31912), we get a palindrome (21944912).

The spelling of 21913000 in words is "twenty-one million, nine hundred thirteen thousand".