21938700 has 144 divisors (see below), whose sum is σ = 75106304. Its totient is φ = 4838400.

The previous prime is 21938699. The next prime is 21938713. The reversal of 21938700 is 783912.

It is a happy number.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 64932 + ... + 65268.

Almost surely, 2^21938700 is an apocalyptic number.

21938700 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 21938700, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37553152).

21938700 is an abundant number, since it is smaller than the sum of its proper divisors (53167604).

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

21938700 is a wasteful number, since it uses less digits than its factorization.

21938700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 392 (or 385 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 21938700 is about 4683.8765995701. The cubic root of 21938700 is about 279.9434409570.

The spelling of 21938700 in words is "twenty-one million, nine hundred thirty-eight thousand, seven hundred".