81641059021 has 8 divisors (see below), whose sum is σ = 82605650688. Its totient is φ = 80681640000.

The previous prime is 81641059013. The next prime is 81641059067. The reversal of 81641059021 is 12095014618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81641059021 - 2³ = 81641059013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81641059001) 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, 1261405 + ... + 1324546.

It is an arithmetic number, because the mean of its divisors is an integer number (10325706336).

Almost surely, 2^81641059021 is an apocalyptic number.

It is an amenable number.

81641059021 is a deficient number, since it is larger than the sum of its proper divisors (964591667).

81641059021 is a wasteful number, since it uses less digits than its factorization.

81641059021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2586323.

The product of its (nonzero) digits is 17280, while the sum is 37.

The spelling of 81641059021 in words is "eighty-one billion, six hundred forty-one million, fifty-nine thousand, twenty-one".