7131891691 has 4 divisors (see below), whose sum is σ = 7197322000. Its totient is φ = 7066461384.

The previous prime is 7131891631. The next prime is 7131891703. The reversal of 7131891691 is 1961981317.

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 7131891691 - 2⁷ = 7131891563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7131891601) 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, 32714991 + ... + 32715208.

It is an arithmetic number, because the mean of its divisors is an integer number (1799330500).

Almost surely, 2^7131891691 is an apocalyptic number.

7131891691 is a deficient number, since it is larger than the sum of its proper divisors (65430309).

7131891691 is a wasteful number, since it uses less digits than its factorization.

7131891691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65430308.

The product of its digits is 81648, while the sum is 46.

The square root of 7131891691 is about 84450.5280682128. The cubic root of 7131891691 is about 1924.8707792947.

The spelling of 7131891691 in words is "seven billion, one hundred thirty-one million, eight hundred ninety-one thousand, six hundred ninety-one".