81743964939 has 128 divisors (see below), whose sum is σ = 151934720000. Its totient is φ = 42287132160.

The previous prime is 81743964899. The next prime is 81743964943. The reversal of 81743964939 is 93946934718.

81743964939 is a `hidden beast` number, since 8 + 17 + 43 + 96 + 493 + 9 = 666.

It is not a de Polignac number, because 81743964939 - 2⁹ = 81743964427 is a prime.

It is a super-2 number, since 2×81743964939² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (81743964539) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 74788077 + ... + 74789169.

It is an arithmetic number, because the mean of its divisors is an integer number (1186990000).

Almost surely, 2^81743964939 is an apocalyptic number.

81743964939 is a deficient number, since it is larger than the sum of its proper divisors (70190755061).

81743964939 is a wasteful number, since it uses less digits than its factorization.

81743964939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1682 (or 1676 counting only the distinct ones).

The product of its digits is 35271936, while the sum is 63.

The spelling of 81743964939 in words is "eighty-one billion, seven hundred forty-three million, nine hundred sixty-four thousand, nine hundred thirty-nine".