21099894 has 16 divisors (see below), whose sum is σ = 42435120. Its totient is φ = 6994080.

The previous prime is 21099889. The next prime is 21099913. The reversal of 21099894 is 49899012.

It is a super-2 number, since 2×21099894² = 890411053622472, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8629 + ... + 10800.

It is an arithmetic number, because the mean of its divisors is an integer number (2652195).

Almost surely, 2^21099894 is an apocalyptic number.

21099894 is an abundant number, since it is smaller than the sum of its proper divisors (21335226).

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

21099894 is a wasteful number, since it uses less digits than its factorization.

21099894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19615.

The product of its (nonzero) digits is 46656, while the sum is 42.

The square root of 21099894 is about 4593.4620930187. The cubic root of 21099894 is about 276.3291860926.

The spelling of 21099894 in words is "twenty-one million, ninety-nine thousand, eight hundred ninety-four".