1557166081 has 2 divisors, whose sum is σ = 1557166082. Its totient is φ = 1557166080.

The previous prime is 1557166073. The next prime is 1557166087. The reversal of 1557166081 is 1806617551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1327946481 + 229219600 = 36441^2 + 15140^2 .

It is a cyclic number.

It is not a de Polignac number, because 1557166081 - 2³ = 1557166073 is a prime.

It is a super-2 number, since 2×1557166081² = 4849532407633797122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1557166087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 778583040 + 778583041.

It is an arithmetic number, because the mean of its divisors is an integer number (778583041).

Almost surely, 2^1557166081 is an apocalyptic number.

It is an amenable number.

1557166081 is a deficient number, since it is larger than the sum of its proper divisors (1).

1557166081 is an equidigital number, since it uses as much as digits as its factorization.

1557166081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 50400, while the sum is 40.

The square root of 1557166081 is about 39460.9437418823. The cubic root of 1557166081 is about 1159.0752838989.

The spelling of 1557166081 in words is "one billion, five hundred fifty-seven million, one hundred sixty-six thousand, eighty-one".