81940859406 has 48 divisors (see below), whose sum is σ = 203743164768. Its totient is φ = 23314521600.

The previous prime is 81940859393. The next prime is 81940859411. The reversal of 81940859406 is 60495804918.

81940859406 is a `hidden beast` number, since 8 + 1 + 9 + 40 + 8 + 594 + 0 + 6 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1318855 + ... + 1379586.

It is an arithmetic number, because the mean of its divisors is an integer number (4244649266).

Almost surely, 2^81940859406 is an apocalyptic number.

81940859406 is an abundant number, since it is smaller than the sum of its proper divisors (121802305362).

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

81940859406 is a wasteful number, since it uses less digits than its factorization.

81940859406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2698697 (or 2698694 counting only the distinct ones).

The product of its (nonzero) digits is 2488320, while the sum is 54.

The spelling of 81940859406 in words is "eighty-one billion, nine hundred forty million, eight hundred fifty-nine thousand, four hundred six".