121557713579 has 2 divisors, whose sum is σ = 121557713580. Its totient is φ = 121557713578.

The previous prime is 121557713561. The next prime is 121557713663. The reversal of 121557713579 is 975317755121.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121557713579 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 121557713579.

It is not a weakly prime, because it can be changed into another prime (121557713509) 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, 60778856789 + 60778856790.

It is an arithmetic number, because the mean of its divisors is an integer number (60778856790).

Almost surely, 2^121557713579 is an apocalyptic number.

121557713579 is a deficient number, since it is larger than the sum of its proper divisors (1).

121557713579 is an equidigital number, since it uses as much as digits as its factorization.

121557713579 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2315250, while the sum is 53.

The spelling of 121557713579 in words is "one hundred twenty-one billion, five hundred fifty-seven million, seven hundred thirteen thousand, five hundred seventy-nine".