61318223921 has 2 divisors, whose sum is σ = 61318223922. Its totient is φ = 61318223920.

The previous prime is 61318223893. The next prime is 61318223957. The reversal of 61318223921 is 12932281316.

61318223921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60821424400 + 496799521 = 246620^2 + 22289^2 .

It is a cyclic number.

It is not a de Polignac number, because 61318223921 - 2³⁴ = 44138354737 is a prime.

It is a super-2 number, since 2×61318223921² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (61318223621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30659111960 + 30659111961.

It is an arithmetic number, because the mean of its divisors is an integer number (30659111961).

Almost surely, 2^61318223921 is an apocalyptic number.

It is an amenable number.

61318223921 is a deficient number, since it is larger than the sum of its proper divisors (1).

61318223921 is an equidigital number, since it uses as much as digits as its factorization.

61318223921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31104, while the sum is 38.

The spelling of 61318223921 in words is "sixty-one billion, three hundred eighteen million, two hundred twenty-three thousand, nine hundred twenty-one".