81996157687 has 2 divisors, whose sum is σ = 81996157688. Its totient is φ = 81996157686.

The previous prime is 81996157657. The next prime is 81996157697. The reversal of 81996157687 is 78675169918.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81996157687 - 2¹¹ = 81996155639 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81996157657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40998078843 + 40998078844.

It is an arithmetic number, because the mean of its divisors is an integer number (40998078844).

Almost surely, 2^81996157687 is an apocalyptic number.

81996157687 is a deficient number, since it is larger than the sum of its proper divisors (1).

81996157687 is an equidigital number, since it uses as much as digits as its factorization.

81996157687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45722880, while the sum is 67.

The spelling of 81996157687 in words is "eighty-one billion, nine hundred ninety-six million, one hundred fifty-seven thousand, six hundred eighty-seven".