20215513 has 2 divisors, whose sum is σ = 20215514. Its totient is φ = 20215512.

The previous prime is 20215463. The next prime is 20215529. The reversal of 20215513 is 31551202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18344089 + 1871424 = 4283^2 + 1368^2 .

It is a cyclic number.

It is not a de Polignac number, because 20215513 - 2²¹ = 18118361 is a prime.

It is not a weakly prime, because it can be changed into another prime (20215543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10107756 + 10107757.

It is an arithmetic number, because the mean of its divisors is an integer number (10107757).

Almost surely, 2^20215513 is an apocalyptic number.

It is an amenable number.

20215513 is a deficient number, since it is larger than the sum of its proper divisors (1).

20215513 is an equidigital number, since it uses as much as digits as its factorization.

20215513 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 20215513 is about 4496.1664782345. The cubic root of 20215513 is about 272.4132675745.

Adding to 20215513 its reverse (31551202), we get a palindrome (51766715).

The spelling of 20215513 in words is "twenty million, two hundred fifteen thousand, five hundred thirteen".