21911400 has 288 divisors, whose sum is σ = 88208640. Its totient is φ = 4769280.

The previous prime is 21911399. The next prime is 21911411. The reversal of 21911400 is 411912.

It is a Harshad number since it is a multiple of its sum of digits (18).

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 71 ways as a sum of consecutive naturals, for example, 466177 + ... + 466223.

It is an arithmetic number, because the mean of its divisors is an integer number (306280).

Almost surely, 2^21911400 is an apocalyptic number.

21911400 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 21911400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44104320).

21911400 is an abundant number, since it is smaller than the sum of its proper divisors (66297240).

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

21911400 is a wasteful number, since it uses less digits than its factorization.

21911400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 21911400 is about 4680.9614397045. The cubic root of 21911400 is about 279.8272744238.

The spelling of 21911400 in words is "twenty-one million, nine hundred eleven thousand, four hundred".