991407897826 has 16 divisors (see below), whose sum is σ = 1487708117280. Its totient is φ = 495505241920.

The previous prime is 991407897793. The next prime is 991407897839. The reversal of 991407897826 is 628798704199.

It is a super-3 number, since 3×991407897826³ (a number of 37 digits) contains 333 as substring.

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, 95075625 + ... + 95086051.

It is an arithmetic number, because the mean of its divisors is an integer number (92981757330).

Almost surely, 2^991407897826 is an apocalyptic number.

991407897826 is a deficient number, since it is larger than the sum of its proper divisors (496300219454).

991407897826 is a wasteful number, since it uses less digits than its factorization.

991407897826 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24929.

The product of its (nonzero) digits is 109734912, while the sum is 70.

The spelling of 991407897826 in words is "nine hundred ninety-one billion, four hundred seven million, eight hundred ninety-seven thousand, eight hundred twenty-six".