21753937 has 2 divisors, whose sum is σ = 21753938. Its totient is φ = 21753936.

The previous prime is 21753923. The next prime is 21753961. The reversal of 21753937 is 73935712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18740241 + 3013696 = 4329^2 + 1736^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21753937 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21753896 and 21753905.

It is not a weakly prime, because it can be changed into another prime (21753967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10876968 + 10876969.

It is an arithmetic number, because the mean of its divisors is an integer number (10876969).

Almost surely, 2^21753937 is an apocalyptic number.

It is an amenable number.

21753937 is a deficient number, since it is larger than the sum of its proper divisors (1).

21753937 is an equidigital number, since it uses as much as digits as its factorization.

21753937 is an evil number, because the sum of its binary digits is even.

The product of its digits is 39690, while the sum is 37.

The square root of 21753937 is about 4664.1115981503. Note that the first 3 decimals coincide. The cubic root of 21753937 is about 279.1553499930.

The spelling of 21753937 in words is "twenty-one million, seven hundred fifty-three thousand, nine hundred thirty-seven".