81641696477 has 16 divisors (see below), whose sum is σ = 92649614400. Its totient is φ = 71260035840.

The previous prime is 81641696447. The next prime is 81641696519. The reversal of 81641696477 is 77469614618.

It is a cyclic number.

It is not a de Polignac number, because 81641696477 - 2⁸ = 81641696221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81641696407) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 657788 + ... + 771989.

It is an arithmetic number, because the mean of its divisors is an integer number (5790600900).

Almost surely, 2^81641696477 is an apocalyptic number.

It is an amenable number.

81641696477 is a deficient number, since it is larger than the sum of its proper divisors (11007917923).

81641696477 is a wasteful number, since it uses less digits than its factorization.

81641696477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1429996.

The product of its digits is 12192768, while the sum is 59.

The spelling of 81641696477 in words is "eighty-one billion, six hundred forty-one million, six hundred ninety-six thousand, four hundred seventy-seven".