971888091 has 4 divisors (see below), whose sum is σ = 1295850792. Its totient is φ = 647925392.

The previous prime is 971888087. The next prime is 971888119. The reversal of 971888091 is 190888179.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 971888091 - 2² = 971888087 is a prime.

It is a super-2 number, since 2×971888091² = 1889132922855248562, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (971888591) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 161981346 + ... + 161981351.

It is an arithmetic number, because the mean of its divisors is an integer number (323962698).

Almost surely, 2^971888091 is an apocalyptic number.

971888091 is a deficient number, since it is larger than the sum of its proper divisors (323962701).

971888091 is a wasteful number, since it uses less digits than its factorization.

971888091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323962700.

The product of its (nonzero) digits is 290304, while the sum is 51.

The square root of 971888091 is about 31175.1197431542. The cubic root of 971888091 is about 990.5401572241.

The spelling of 971888091 in words is "nine hundred seventy-one million, eight hundred eighty-eight thousand, ninety-one".