61115166557 has 2 divisors, whose sum is σ = 61115166558. Its totient is φ = 61115166556.

The previous prime is 61115166521. The next prime is 61115166667. The reversal of 61115166557 is 75566151116.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60794792356 + 320374201 = 246566^2 + 17899^2 .

It is a cyclic number.

It is not a de Polignac number, because 61115166557 - 2²² = 61110972253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61115166257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30557583278 + 30557583279.

It is an arithmetic number, because the mean of its divisors is an integer number (30557583279).

Almost surely, 2^61115166557 is an apocalyptic number.

It is an amenable number.

61115166557 is a deficient number, since it is larger than the sum of its proper divisors (1).

61115166557 is an equidigital number, since it uses as much as digits as its factorization.

61115166557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 189000, while the sum is 44.

The spelling of 61115166557 in words is "sixty-one billion, one hundred fifteen million, one hundred sixty-six thousand, five hundred fifty-seven".