81372819631 has 8 divisors (see below), whose sum is σ = 81964229760. Its totient is φ = 80782649688.

The previous prime is 81372819557. The next prime is 81372819673. The reversal of 81372819631 is 13691827318.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81372819631 is a prime.

It is a super-2 number, since 2×81372819631² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81372819131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 178141 + ... + 440998.

It is an arithmetic number, because the mean of its divisors is an integer number (10245528720).

Almost surely, 2^81372819631 is an apocalyptic number.

81372819631 is a deficient number, since it is larger than the sum of its proper divisors (591410129).

81372819631 is a wasteful number, since it uses less digits than its factorization.

81372819631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 620093.

The product of its digits is 435456, while the sum is 49.

The spelling of 81372819631 in words is "eighty-one billion, three hundred seventy-two million, eight hundred nineteen thousand, six hundred thirty-one".