21899807 has 4 divisors (see below), whose sum is σ = 21910056. Its totient is φ = 21889560.

The previous prime is 21899803. The next prime is 21899831. The reversal of 21899807 is 70899812.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21899807 - 2² = 21899803 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21899803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 569 + ... + 6642.

It is an arithmetic number, because the mean of its divisors is an integer number (5477514).

Almost surely, 2^21899807 is an apocalyptic number.

21899807 is a deficient number, since it is larger than the sum of its proper divisors (10249).

21899807 is an equidigital number, since it uses as much as digits as its factorization.

21899807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10248.

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 21899807 is about 4679.7229618857. The cubic root of 21899807 is about 279.7779148837. Note that the first 3 decimals are identical.

The spelling of 21899807 in words is "twenty-one million, eight hundred ninety-nine thousand, eight hundred seven".