1555091998 has 16 divisors (see below), whose sum is σ = 2490917760. Its totient is φ = 726516000.

The previous prime is 1555091987. The next prime is 1555092023. The reversal of 1555091998 is 8991905551.

It is a super-2 number, since 2×1555091998² = 4836622244487264008, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 430653 + ... + 434248.

It is an arithmetic number, because the mean of its divisors is an integer number (155682360).

Almost surely, 2^1555091998 is an apocalyptic number.

1555091998 is a deficient number, since it is larger than the sum of its proper divisors (935825762).

1555091998 is a wasteful number, since it uses less digits than its factorization.

1555091998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 864963.

The product of its (nonzero) digits is 729000, while the sum is 52.

The square root of 1555091998 is about 39434.6547848463. The cubic root of 1555091998 is about 1158.5604412597.

The spelling of 1555091998 in words is "one billion, five hundred fifty-five million, ninety-one thousand, nine hundred ninety-eight".