21187045 has 16 divisors (see below), whose sum is σ = 27874368. Its totient is φ = 15331840.

The previous prime is 21187027. The next prime is 21187063. The reversal of 21187045 is 54078112.

It is an interprime number because it is at equal distance from previous prime (21187027) and next prime (21187063).

It is not a de Polignac number, because 21187045 - 2⁵ = 21187013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11637 + ... + 13333.

It is an arithmetic number, because the mean of its divisors is an integer number (1742148).

Almost surely, 2^21187045 is an apocalyptic number.

It is an amenable number.

21187045 is a deficient number, since it is larger than the sum of its proper divisors (6687323).

21187045 is a wasteful number, since it uses less digits than its factorization.

21187045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1940.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 21187045 is about 4602.9387351995. The cubic root of 21187045 is about 276.7091135016.

The spelling of 21187045 in words is "twenty-one million, one hundred eighty-seven thousand, forty-five".