81835727621 has 8 divisors (see below), whose sum is σ = 86147014080. Its totient is φ = 77524855488.

The previous prime is 81835727557. The next prime is 81835727639. The reversal of 81835727621 is 12672753818.

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

It is not a de Polignac number, because 81835727621 - 2⁶ = 81835727557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81835727621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81835727021) 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, 353645 + ... + 537341.

It is an arithmetic number, because the mean of its divisors is an integer number (10768376760).

Almost surely, 2^81835727621 is an apocalyptic number.

It is an amenable number.

81835727621 is a deficient number, since it is larger than the sum of its proper divisors (4311286459).

81835727621 is a wasteful number, since it uses less digits than its factorization.

81835727621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207163.

The product of its digits is 1128960, while the sum is 50.

The spelling of 81835727621 in words is "eighty-one billion, eight hundred thirty-five million, seven hundred twenty-seven thousand, six hundred twenty-one".