1556955121 has 2 divisors, whose sum is σ = 1556955122. Its totient is φ = 1556955120.

The previous prime is 1556955089. The next prime is 1556955139. The reversal of 1556955121 is 1215596551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 947408400 + 609546721 = 30780^2 + 24689^2 .

It is a cyclic number.

It is not a de Polignac number, because 1556955121 - 2⁵ = 1556955089 is a prime.

It is not a weakly prime, because it can be changed into another prime (1556955151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 778477560 + 778477561.

It is an arithmetic number, because the mean of its divisors is an integer number (778477561).

Almost surely, 2^1556955121 is an apocalyptic number.

It is an amenable number.

1556955121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1556955121 is an equidigital number, since it uses as much as digits as its factorization.

1556955121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 67500, while the sum is 40.

The square root of 1556955121 is about 39458.2706286021. The cubic root of 1556955121 is about 1159.0229389012.

The spelling of 1556955121 in words is "one billion, five hundred fifty-six million, nine hundred fifty-five thousand, one hundred twenty-one".