991687719 has 16 divisors (see below), whose sum is σ = 1448501760. Its totient is φ = 598503360.

The previous prime is 991687693. The next prime is 991687747. The reversal of 991687719 is 917786199.

It is not a de Polignac number, because 991687719 - 2⁵ = 991687687 is a prime.

It is a super-2 number, since 2×991687719² = 1966889064030845922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991687759) 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, 54982 + ... + 70755.

It is an arithmetic number, because the mean of its divisors is an integer number (90531360).

Almost surely, 2^991687719 is an apocalyptic number.

991687719 is a deficient number, since it is larger than the sum of its proper divisors (456814041).

991687719 is a wasteful number, since it uses less digits than its factorization.

991687719 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125990.

The product of its digits is 1714608, while the sum is 57.

The square root of 991687719 is about 31491.0736400015. The cubic root of 991687719 is about 997.2215269038.

The spelling of 991687719 in words is "nine hundred ninety-one million, six hundred eighty-seven thousand, seven hundred nineteen".