1556555149 has 2 divisors, whose sum is σ = 1556555150. Its totient is φ = 1556555148.

The previous prime is 1556555141. The next prime is 1556555179. The reversal of 1556555149 is 9415556551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 995718025 + 560837124 = 31555^2 + 23682^2 .

It is a cyclic number.

It is not a de Polignac number, because 1556555149 - 2³ = 1556555141 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1556555099 and 1556555108.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1556555141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 778277574 + 778277575.

It is an arithmetic number, because the mean of its divisors is an integer number (778277575).

Almost surely, 2^1556555149 is an apocalyptic number.

It is an amenable number.

1556555149 is a deficient number, since it is larger than the sum of its proper divisors (1).

1556555149 is an equidigital number, since it uses as much as digits as its factorization.

1556555149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 675000, while the sum is 46.

The square root of 1556555149 is about 39453.2020120040. The cubic root of 1556555149 is about 1158.9236818280.

The spelling of 1556555149 in words is "one billion, five hundred fifty-six million, five hundred fifty-five thousand, one hundred forty-nine".