1556991055 has 4 divisors (see below), whose sum is σ = 1868389272. Its totient is φ = 1245592840.

The previous prime is 1556991047. The next prime is 1556991083. The reversal of 1556991055 is 5501996551.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 1556991055 - 2³ = 1556991047 is a prime.

It is a super-2 number, since 2×1556991055² = 4848442290700026050, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1556990996 and 1556991014.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 155699101 + ... + 155699110.

It is an arithmetic number, because the mean of its divisors is an integer number (467097318).

Almost surely, 2^1556991055 is an apocalyptic number.

1556991055 is a deficient number, since it is larger than the sum of its proper divisors (311398217).

1556991055 is an equidigital number, since it uses as much as digits as its factorization.

1556991055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311398216.

The product of its (nonzero) digits is 303750, while the sum is 46.

The square root of 1556991055 is about 39458.7259677755. The cubic root of 1556991055 is about 1159.0318554523.

The spelling of 1556991055 in words is "one billion, five hundred fifty-six million, nine hundred ninety-one thousand, fifty-five".