81640462137 has 16 divisors (see below), whose sum is σ = 117875005248. Its totient is φ = 49962709440.

The previous prime is 81640462133. The next prime is 81640462147. The reversal of 81640462137 is 73126404618.

It is not a de Polignac number, because 81640462137 - 2² = 81640462133 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81640462133) 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, 5775663 + ... + 5789780.

It is an arithmetic number, because the mean of its divisors is an integer number (7367187828).

Almost surely, 2^81640462137 is an apocalyptic number.

It is an amenable number.

81640462137 is a deficient number, since it is larger than the sum of its proper divisors (36234543111).

81640462137 is a wasteful number, since it uses less digits than its factorization.

81640462137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11565640.

The product of its (nonzero) digits is 193536, while the sum is 42.

The spelling of 81640462137 in words is "eighty-one billion, six hundred forty million, four hundred sixty-two thousand, one hundred thirty-seven".