20215261613 has 2 divisors, whose sum is σ = 20215261614. Its totient is φ = 20215261612.

The previous prime is 20215261607. The next prime is 20215261667. The reversal of 20215261613 is 31616251202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18849367849 + 1365893764 = 137293^2 + 36958^2 .

It is a cyclic number.

It is not a de Polignac number, because 20215261613 - 2¹⁰ = 20215260589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20215261013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10107630806 + 10107630807.

It is an arithmetic number, because the mean of its divisors is an integer number (10107630807).

Almost surely, 2^20215261613 is an apocalyptic number.

It is an amenable number.

20215261613 is a deficient number, since it is larger than the sum of its proper divisors (1).

20215261613 is an equidigital number, since it uses as much as digits as its factorization.

20215261613 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 29.

The spelling of 20215261613 in words is "twenty billion, two hundred fifteen million, two hundred sixty-one thousand, six hundred thirteen".