21753945 has 24 divisors (see below), whose sum is σ = 37919232. Its totient is φ = 11536800.

The previous prime is 21753937. The next prime is 21753961. The reversal of 21753945 is 54935712.

It is not a de Polignac number, because 21753945 - 2³ = 21753937 is a prime.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 7330 + ... + 9860.

It is an arithmetic number, because the mean of its divisors is an integer number (1579968).

Almost surely, 2^21753945 is an apocalyptic number.

It is an amenable number.

21753945 is a deficient number, since it is larger than the sum of its proper divisors (16165287).

21753945 is a wasteful number, since it uses less digits than its factorization.

21753945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2733 (or 2730 counting only the distinct ones).

The product of its digits is 37800, while the sum is 36.

The square root of 21753945 is about 4664.1124557626. The cubic root of 21753945 is about 279.1553842127.

The spelling of 21753945 in words is "twenty-one million, seven hundred fifty-three thousand, nine hundred forty-five".