21545745 has 16 divisors (see below), whose sum is σ = 37125312. Its totient is φ = 10607040.

The previous prime is 21545723. The next prime is 21545759. The reversal of 21545745 is 54754512.

It is not a de Polignac number, because 21545745 - 2⁹ = 21545233 is a prime.

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, 55051 + ... + 55440.

It is an arithmetic number, because the mean of its divisors is an integer number (2320332).

Almost surely, 2^21545745 is an apocalyptic number.

It is an amenable number.

21545745 is a deficient number, since it is larger than the sum of its proper divisors (15579567).

21545745 is a wasteful number, since it uses less digits than its factorization.

21545745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110512.

The product of its digits is 28000, while the sum is 33.

The square root of 21545745 is about 4641.7394368922. The cubic root of 21545745 is about 278.2619591411.

The spelling of 21545745 in words is "twenty-one million, five hundred forty-five thousand, seven hundred forty-five".