21745753 has 4 divisors (see below), whose sum is σ = 21765348. Its totient is φ = 21726160.

The previous prime is 21745733. The next prime is 21745769. The reversal of 21745753 is 35754712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13520329 + 8225424 = 3677^2 + 2868^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21745753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21745733) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8026 + ... + 10387.

It is an arithmetic number, because the mean of its divisors is an integer number (5441337).

Almost surely, 2^21745753 is an apocalyptic number.

It is an amenable number.

21745753 is a deficient number, since it is larger than the sum of its proper divisors (19595).

21745753 is a wasteful number, since it uses less digits than its factorization.

21745753 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19594.

The product of its digits is 29400, while the sum is 34.

The square root of 21745753 is about 4663.2341781214. The cubic root of 21745753 is about 279.1203387988.

The spelling of 21745753 in words is "twenty-one million, seven hundred forty-five thousand, seven hundred fifty-three".