21994100 has 18 divisors (see below), whose sum is σ = 47727414. Its totient is φ = 8797600.

The previous prime is 21994069. The next prime is 21994111. The reversal of 21994100 is 149912.

It can be written as a sum of positive squares in 3 ways, for example, as 2298256 + 19695844 = 1516^2 + 4438^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21994100.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 109871 + ... + 110070.

It is an arithmetic number, because the mean of its divisors is an integer number (2651523).

Almost surely, 2^21994100 is an apocalyptic number.

21994100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21994100 is an abundant number, since it is smaller than the sum of its proper divisors (25733314).

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

21994100 is a wasteful number, since it uses less digits than its factorization.

21994100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219955 (or 219948 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 21994100 is about 4689.7867755368. The cubic root of 21994100 is about 280.1788822926.

The spelling of 21994100 in words is "twenty-one million, nine hundred ninety-four thousand, one hundred".