81030721368 has 32 divisors (see below), whose sum is σ = 202703430960. Its totient is φ = 26993356800.

The previous prime is 81030721367. The next prime is 81030721379. The reversal of 81030721368 is 86312703018.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81030721361) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1016005 + ... + 1092852.

Almost surely, 2^81030721368 is an apocalyptic number.

It is an amenable number.

81030721368 is an abundant number, since it is smaller than the sum of its proper divisors (121672709592).

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

81030721368 is a wasteful number, since it uses less digits than its factorization.

81030721368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2110467 (or 2110463 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 39.

The spelling of 81030721368 in words is "eighty-one billion, thirty million, seven hundred twenty-one thousand, three hundred sixty-eight".