21970513 has 2 divisors, whose sum is σ = 21970514. Its totient is φ = 21970512.

The previous prime is 21970499. The next prime is 21970577. The reversal of 21970513 is 31507912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15904144 + 6066369 = 3988^2 + 2463^2 .

It is a cyclic number.

It is not a de Polignac number, because 21970513 - 2²¹ = 19873361 is a prime.

It is not a weakly prime, because it can be changed into another prime (21970913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10985256 + 10985257.

It is an arithmetic number, because the mean of its divisors is an integer number (10985257).

Almost surely, 2^21970513 is an apocalyptic number.

It is an amenable number.

21970513 is a deficient number, since it is larger than the sum of its proper divisors (1).

21970513 is an equidigital number, since it uses as much as digits as its factorization.

21970513 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 21970513 is about 4687.2713810916. The cubic root of 21970513 is about 280.0786896181.

The spelling of 21970513 in words is "twenty-one million, nine hundred seventy thousand, five hundred thirteen".