81214974639 has 6 divisors (see below), whose sum is σ = 117310518936. Its totient is φ = 54143316420.

The previous prime is 81214974613. The next prime is 81214974649. The reversal of 81214974639 is 93647941218.

81214974639 is a `hidden beast` number, since 81 + 2 + 1 + 497 + 46 + 39 = 666.

It is not a de Polignac number, because 81214974639 - 2¹¹ = 81214972591 is a prime.

It is a super-2 number, since 2×81214974639² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81214974649) 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 5 ways as a sum of consecutive naturals, for example, 4511943027 + ... + 4511943044.

It is an arithmetic number, because the mean of its divisors is an integer number (19551753156).

Almost surely, 2^81214974639 is an apocalyptic number.

81214974639 is a deficient number, since it is larger than the sum of its proper divisors (36095544297).

81214974639 is a wasteful number, since it uses less digits than its factorization.

81214974639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9023886077 (or 9023886074 counting only the distinct ones).

The product of its digits is 2612736, while the sum is 54.

The spelling of 81214974639 in words is "eighty-one billion, two hundred fourteen million, nine hundred seventy-four thousand, six hundred thirty-nine".