85777131631 has 4 divisors (see below), whose sum is σ = 86626410264. Its totient is φ = 84927853000.

The previous prime is 85777131617. The next prime is 85777131641. The reversal of 85777131631 is 13613177758.

It is a happy number.

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 85777131631 - 2²³ = 85768743023 is a prime.

It is a super-2 number, since 2×85777131631² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (85777131641) 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, 424639165 + ... + 424639366.

It is an arithmetic number, because the mean of its divisors is an integer number (21656602566).

Almost surely, 2^85777131631 is an apocalyptic number.

85777131631 is a deficient number, since it is larger than the sum of its proper divisors (849278633).

85777131631 is a wasteful number, since it uses less digits than its factorization.

85777131631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 849278632.

The product of its digits is 740880, while the sum is 49.

The spelling of 85777131631 in words is "eighty-five billion, seven hundred seventy-seven million, one hundred thirty-one thousand, six hundred thirty-one".