1991183715 has 80 divisors (see below), whose sum is σ = 3748320576. Its totient is φ = 1009324800.

The previous prime is 1991183687. The next prime is 1991183759. The reversal of 1991183715 is 5173811991.

It is a happy number.

It is not a de Polignac number, because 1991183715 - 2⁹ = 1991183203 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1685425 + ... + 1686605.

Almost surely, 2^1991183715 is an apocalyptic number.

1991183715 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1991183715 is a deficient number, since it is larger than the sum of its proper divisors (1757136861).

1991183715 is a wasteful number, since it uses less digits than its factorization.

1991183715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1402 (or 1393 counting only the distinct ones).

The product of its digits is 68040, while the sum is 45.

The square root of 1991183715 is about 44622.6816204495. The cubic root of 1991183715 is about 1258.0670191008.

The spelling of 1991183715 in words is "one billion, nine hundred ninety-one million, one hundred eighty-three thousand, seven hundred fifteen".