75631991 has 4 divisors (see below), whose sum is σ = 75736752. Its totient is φ = 75527232.

The previous prime is 75631949. The next prime is 75631999. The reversal of 75631991 is 19913657.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19913657 = 1801 ⋅11057.

It is a cyclic number.

It is not a de Polignac number, because 75631991 - 2¹⁰ = 75630967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (75631999) 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, 51290 + ... + 52743.

It is an arithmetic number, because the mean of its divisors is an integer number (18934188).

Almost surely, 2^75631991 is an apocalyptic number.

75631991 is a deficient number, since it is larger than the sum of its proper divisors (104761).

75631991 is a wasteful number, since it uses less digits than its factorization.

75631991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104760.

The product of its digits is 51030, while the sum is 41.

The square root of 75631991 is about 8696.6655104126. The cubic root of 75631991 is about 422.8975584055.

The spelling of 75631991 in words is "seventy-five million, six hundred thirty-one thousand, nine hundred ninety-one".