1557661898 has 32 divisors (see below), whose sum is σ = 2612639232. Its totient is φ = 691646400.

The previous prime is 1557661871. The next prime is 1557662003. The reversal of 1557661898 is 8981667551.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 133853 + ... + 145023.

It is an arithmetic number, because the mean of its divisors is an integer number (81644976).

Almost surely, 2^1557661898 is an apocalyptic number.

1557661898 is a deficient number, since it is larger than the sum of its proper divisors (1054977334).

1557661898 is a wasteful number, since it uses less digits than its factorization.

1557661898 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11390.

The product of its digits is 3628800, while the sum is 56.

The square root of 1557661898 is about 39467.2256182266. The cubic root of 1557661898 is about 1159.1982911688.

The spelling of 1557661898 in words is "one billion, five hundred fifty-seven million, six hundred sixty-one thousand, eight hundred ninety-eight".