21899700 has 72 divisors (see below), whose sum is σ = 70412160. Its totient is φ = 5839200.

The previous prime is 21899677. The next prime is 21899707. The reversal of 21899700 is 799812.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21899707) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1356 + ... + 6755.

Almost surely, 2^21899700 is an apocalyptic number.

21899700 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 21899700, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35206080).

21899700 is an abundant number, since it is smaller than the sum of its proper divisors (48512460).

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

21899700 is a wasteful number, since it uses less digits than its factorization.

21899700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8134 (or 8121 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The square root of 21899700 is about 4679.7115295710. The cubic root of 21899700 is about 279.7774592284. Note that the first 3 decimals are identical.

The spelling of 21899700 in words is "twenty-one million, eight hundred ninety-nine thousand, seven hundred".