20765513 has 2 divisors, whose sum is σ = 20765514. Its totient is φ = 20765512.

The previous prime is 20765509. The next prime is 20765531. The reversal of 20765513 is 31556702.

Together with next prime (20765531) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11505664 + 9259849 = 3392^2 + 3043^2 .

It is a cyclic number.

It is not a de Polignac number, because 20765513 - 2² = 20765509 is a prime.

It is not a weakly prime, because it can be changed into another prime (20765413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10382756 + 10382757.

It is an arithmetic number, because the mean of its divisors is an integer number (10382757).

Almost surely, 2^20765513 is an apocalyptic number.

It is an amenable number.

20765513 is a deficient number, since it is larger than the sum of its proper divisors (1).

20765513 is an equidigital number, since it uses as much as digits as its factorization.

20765513 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6300, while the sum is 29.

The square root of 20765513 is about 4556.9192444019. The cubic root of 20765513 is about 274.8616957443.

The spelling of 20765513 in words is "twenty million, seven hundred sixty-five thousand, five hundred thirteen".