20715641 has 2 divisors, whose sum is σ = 20715642. Its totient is φ = 20715640.

The previous prime is 20715623. The next prime is 20715647. The reversal of 20715641 is 14651702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13719616 + 6996025 = 3704^2 + 2645^2 .

It is a cyclic number.

It is not a de Polignac number, because 20715641 - 2⁶ = 20715577 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20715641.

It is not a weakly prime, because it can be changed into another prime (20715647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10357820 + 10357821.

It is an arithmetic number, because the mean of its divisors is an integer number (10357821).

Almost surely, 2^20715641 is an apocalyptic number.

It is an amenable number.

20715641 is a deficient number, since it is larger than the sum of its proper divisors (1).

20715641 is an equidigital number, since it uses as much as digits as its factorization.

20715641 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 20715641 is about 4551.4438368500. The cubic root of 20715641 is about 274.6414765901.

The spelling of 20715641 in words is "twenty million, seven hundred fifteen thousand, six hundred forty-one".