21899145 has 32 divisors (see below), whose sum is σ = 37404288. Its totient is φ = 10902528.

The previous prime is 21899117. The next prime is 21899159. The reversal of 21899145 is 54199812.

It is not a de Polignac number, because 21899145 - 2⁸ = 21898889 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 39762 + ... + 40308.

It is an arithmetic number, because the mean of its divisors is an integer number (1168884).

Almost surely, 2^21899145 is an apocalyptic number.

It is an amenable number.

21899145 is a deficient number, since it is larger than the sum of its proper divisors (15505143).

21899145 is a wasteful number, since it uses less digits than its factorization.

21899145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 729.

The product of its digits is 25920, while the sum is 39.

The square root of 21899145 is about 4679.6522306684. The cubic root of 21899145 is about 279.7750957592.

The spelling of 21899145 in words is "twenty-one million, eight hundred ninety-nine thousand, one hundred forty-five".