1555013891 has 4 divisors (see below), whose sum is σ = 1580505984. Its totient is φ = 1529521800.

The previous prime is 1555013861. The next prime is 1555013899. The reversal of 1555013891 is 1983105551.

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

It is a cyclic number.

It is not a de Polignac number, because 1555013891 - 2¹⁸ = 1554751747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1555013899) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12745955 + ... + 12746076.

It is an arithmetic number, because the mean of its divisors is an integer number (395126496).

Almost surely, 2^1555013891 is an apocalyptic number.

1555013891 is a deficient number, since it is larger than the sum of its proper divisors (25492093).

1555013891 is an equidigital number, since it uses as much as digits as its factorization.

1555013891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25492092.

The product of its (nonzero) digits is 27000, while the sum is 38.

The square root of 1555013891 is about 39433.6644378886. The cubic root of 1555013891 is about 1158.5410440803.

The spelling of 1555013891 in words is "one billion, five hundred fifty-five million, thirteen thousand, eight hundred ninety-one".