61621365613 has 2 divisors, whose sum is σ = 61621365614. Its totient is φ = 61621365612.

The previous prime is 61621365601. The next prime is 61621365671. The reversal of 61621365613 is 31656312616.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 61502512009 + 118853604 = 247997^2 + 10902^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61621365613 is a prime.

It is a super-2 number, since 2×61621365613² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61621365683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30810682806 + 30810682807.

It is an arithmetic number, because the mean of its divisors is an integer number (30810682807).

Almost surely, 2^61621365613 is an apocalyptic number.

It is an amenable number.

61621365613 is a deficient number, since it is larger than the sum of its proper divisors (1).

61621365613 is an equidigital number, since it uses as much as digits as its factorization.

61621365613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 116640, while the sum is 40.

The spelling of 61621365613 in words is "sixty-one billion, six hundred twenty-one million, three hundred sixty-five thousand, six hundred thirteen".