21691200 has 84 divisors (see below), whose sum is σ = 71180960. Its totient is φ = 5783040.

The previous prime is 21691193. The next prime is 21691207. The reversal of 21691200 is 219612.

It is an interprime number because it is at equal distance from previous prime (21691193) and next prime (21691207).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21691207) 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, 2541 + ... + 7059.

Almost surely, 2^21691200 is an apocalyptic number.

21691200 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 21691200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35590480).

21691200 is an abundant number, since it is smaller than the sum of its proper divisors (49489760).

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

21691200 is a wasteful number, since it uses less digits than its factorization.

21691200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4544 (or 4529 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 21691200 is about 4657.3812384214. The cubic root of 21691200 is about 278.8867360552.

The spelling of 21691200 in words is "twenty-one million, six hundred ninety-one thousand, two hundred".