81642538670 has 128 divisors (see below), whose sum is σ = 187956882432. Its totient is φ = 24791961600.

The previous prime is 81642538669. The next prime is 81642538723. The reversal of 81642538670 is 7683524618.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 13936382 + ... + 13942238.

It is an arithmetic number, because the mean of its divisors is an integer number (1468413144).

Almost surely, 2^81642538670 is an apocalyptic number.

81642538670 is an abundant number, since it is smaller than the sum of its proper divisors (106314343762).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81642538670 is a wasteful number, since it uses less digits than its factorization.

81642538670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6346.

The product of its (nonzero) digits is 1935360, while the sum is 50.

The spelling of 81642538670 in words is "eighty-one billion, six hundred forty-two million, five hundred thirty-eight thousand, six hundred seventy".