21997600 has 72 divisors (see below), whose sum is σ = 55496448. Its totient is φ = 8505600.

The previous prime is 21997589. The next prime is 21997603. The reversal of 21997600 is 679912.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21997603) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24357 + ... + 25243.

It is an arithmetic number, because the mean of its divisors is an integer number (770784).

Almost surely, 2^21997600 is an apocalyptic number.

21997600 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 21997600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27748224).

21997600 is an abundant number, since it is smaller than the sum of its proper divisors (33498848).

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

21997600 is a wasteful number, since it uses less digits than its factorization.

21997600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 938 (or 925 counting only the distinct ones).

The product of its (nonzero) digits is 6804, while the sum is 34.

The square root of 21997600 is about 4690.1599119859. The cubic root of 21997600 is about 280.1937434611.

The spelling of 21997600 in words is "twenty-one million, nine hundred ninety-seven thousand, six hundred".