21899730 has 16 divisors (see below), whose sum is σ = 52559424. Its totient is φ = 5839920.

The previous prime is 21899719. The next prime is 21899743. The reversal of 21899730 is 3799812.

It is a Curzon 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, 364966 + ... + 365025.

It is an arithmetic number, because the mean of its divisors is an integer number (3284964).

Almost surely, 2^21899730 is an apocalyptic number.

21899730 is an abundant number, since it is smaller than the sum of its proper divisors (30659694).

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

21899730 is a wasteful number, since it uses less digits than its factorization.

21899730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 730001.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 21899730 is about 4679.7147348957. The cubic root of 21899730 is about 279.7775869824. Note that the first 3 decimals are identical.

The spelling of 21899730 in words is "twenty-one million, eight hundred ninety-nine thousand, seven hundred thirty".