81640349942 has 32 divisors (see below), whose sum is σ = 131275468800. Its totient is φ = 37941890688.

The previous prime is 81640349941. The next prime is 81640349963. The reversal of 81640349942 is 24994304618.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81640349941) 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, 13426859 + ... + 13432937.

It is an arithmetic number, because the mean of its divisors is an integer number (4102358400).

Almost surely, 2^81640349942 is an apocalyptic number.

81640349942 is a deficient number, since it is larger than the sum of its proper divisors (49635118858).

81640349942 is a wasteful number, since it uses less digits than its factorization.

81640349942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10940.

The product of its (nonzero) digits is 1492992, while the sum is 50.

The spelling of 81640349942 in words is "eighty-one billion, six hundred forty million, three hundred forty-nine thousand, nine hundred forty-two".