80991001 has 8 divisors (see below), whose sum is σ = 99681344. Its totient is φ = 64080720.

The previous prime is 80990993. The next prime is 80991017. The reversal of 80991001 is 10019908.

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

It is a cyclic number.

It is not a de Polignac number, because 80991001 - 2³ = 80990993 is a prime.

It is the 9000-th Hogben number.

It is not an unprimeable number, because it can be changed into a prime (80991041) by changing a digit.

It is a nontrivial repunit in base 8999.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 444915 + ... + 445096.

It is an arithmetic number, because the mean of its divisors is an integer number (12460168).

Almost surely, 2^80991001 is an apocalyptic number.

It is an amenable number.

80991001 is a deficient number, since it is larger than the sum of its proper divisors (18690343).

80991001 is a wasteful number, since it uses less digits than its factorization.

80991001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 890031.

The product of its (nonzero) digits is 648, while the sum is 28.

The square root of 80991001 is about 8999.5000416690. The cubic root of 80991001 is about 432.6588472841.

The spelling of 80991001 in words is "eighty million, nine hundred ninety-one thousand, one".