1998715138 has 16 divisors (see below), whose sum is σ = 3499271424. Its totient is φ = 838366560.

The previous prime is 1998715129. The next prime is 1998715151. The reversal of 1998715138 is 8315178991.

It is a happy 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, 1518123 + ... + 1519438.

It is an arithmetic number, because the mean of its divisors is an integer number (218704464).

Almost surely, 2^1998715138 is an apocalyptic number.

1998715138 is a deficient number, since it is larger than the sum of its proper divisors (1500556286).

1998715138 is a wasteful number, since it uses less digits than its factorization.

1998715138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3037617.

The product of its digits is 544320, while the sum is 52.

The square root of 1998715138 is about 44706.9920482244. The cubic root of 1998715138 is about 1259.6511879841.

The spelling of 1998715138 in words is "one billion, nine hundred ninety-eight million, seven hundred fifteen thousand, one hundred thirty-eight".