21970899 has 16 divisors (see below), whose sum is σ = 32622240. Its totient is φ = 14614560.

The previous prime is 21970891. The next prime is 21970901. The reversal of 21970899 is 99807912.

It is not a de Polignac number, because 21970899 - 2³ = 21970891 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21970891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21009 + ... + 22029.

It is an arithmetic number, because the mean of its divisors is an integer number (2038890).

Almost surely, 2^21970899 is an apocalyptic number.

21970899 is a deficient number, since it is larger than the sum of its proper divisors (10651341).

21970899 is a wasteful number, since it uses less digits than its factorization.

21970899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1827 (or 1821 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 45.

The square root of 21970899 is about 4687.3125562522. The cubic root of 21970899 is about 280.0803298429.

The spelling of 21970899 in words is "twenty-one million, nine hundred seventy thousand, eight hundred ninety-nine".