991507 has 8 divisors (see below), whose sum is σ = 1128960. Its totient is φ = 861960.

The previous prime is 991499. The next prime is 991511. The reversal of 991507 is 705199.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 991507 - 2³ = 991499 is a prime.

It is a super-2 number, since 2×991507² = 1966172262098, which contains 22 as substring.

It is a Duffinian number.

991507 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (991547) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1707 + ... + 2212.

It is an arithmetic number, because the mean of its divisors is an integer number (141120).

2⁹⁹¹⁵⁰⁷ is an apocalyptic number.

991507 is a deficient number, since it is larger than the sum of its proper divisors (137453).

991507 is a wasteful number, since it uses less digits than its factorization.

991507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3953.

The product of its (nonzero) digits is 2835, while the sum is 31.

The square root of 991507 is about 995.7444451264. The cubic root of 991507 is about 99.7160947408.

The spelling of 991507 in words is "nine hundred ninety-one thousand, five hundred seven".