21302745 has 16 divisors (see below), whose sum is σ = 34517760. Its totient is φ = 11217024.

The previous prime is 21302741. The next prime is 21302753. The reversal of 21302745 is 54720312.

It is not a de Polignac number, because 21302745 - 2² = 21302741 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21302741) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7804 + ... + 10173.

It is an arithmetic number, because the mean of its divisors is an integer number (2157360).

Almost surely, 2^21302745 is an apocalyptic number.

It is an amenable number.

21302745 is a deficient number, since it is larger than the sum of its proper divisors (13215015).

21302745 is a wasteful number, since it uses less digits than its factorization.

21302745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18064.

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 21302745 is about 4615.4896814964. The cubic root of 21302745 is about 277.2118915500.

The spelling of 21302745 in words is "twenty-one million, three hundred two thousand, seven hundred forty-five".