89721638621 has 6 divisors (see below), whose sum is σ = 91003127166. Its totient is φ = 88457948600.

The previous prime is 89721638597. The next prime is 89721638627. The reversal of 89721638621 is 12683612798.

It can be written as a sum of positive squares in only one way, i.e., 82032979396 + 7688659225 = 286414^2 + 87685^2 .

It is not a de Polignac number, because 89721638621 - 2¹⁰ = 89721637597 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 (89721638627) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8894150 + ... + 8904231.

It is an arithmetic number, because the mean of its divisors is an integer number (15167187861).

Almost surely, 2^89721638621 is an apocalyptic number.

It is an amenable number.

89721638621 is a deficient number, since it is larger than the sum of its proper divisors (1281488545).

89721638621 is an equidigital number, since it uses as much as digits as its factorization.

89721638621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17798523 (or 17798452 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 53.

The spelling of 89721638621 in words is "eighty-nine billion, seven hundred twenty-one million, six hundred thirty-eight thousand, six hundred twenty-one".