1988999957 has 16 divisors (see below), whose sum is σ = 2387923200. Its totient is φ = 1619768832.

The previous prime is 1988999951. The next prime is 1988999963. The reversal of 1988999957 is 7599998891.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1988999951) and next prime (1988999963).

It is a cyclic number.

It is not a de Polignac number, because 1988999957 - 2⁴ = 1988999941 is a prime.

It is a super-2 number, since 2×1988999957² = 7912241657892003698, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1988999951) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17468 + ... + 65445.

It is an arithmetic number, because the mean of its divisors is an integer number (149245200).

Almost surely, 2^1988999957 is an apocalyptic number.

It is an amenable number.

1988999957 is a deficient number, since it is larger than the sum of its proper divisors (398923243).

1988999957 is a wasteful number, since it uses less digits than its factorization.

1988999957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83092.

The product of its digits is 132269760, while the sum is 74.

The square root of 1988999957 is about 44598.2057598733. The cubic root of 1988999957 is about 1257.6069378523.

The spelling of 1988999957 in words is "one billion, nine hundred eighty-eight million, nine hundred ninety-nine thousand, nine hundred fifty-seven".