8399977621 has 4 divisors (see below), whose sum is σ = 9599974432. Its totient is φ = 7199980812.

The previous prime is 8399977613. The next prime is 8399977673. The reversal of 8399977621 is 1267799938.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1267799938 = 2 ⋅633899969.

It is a cyclic number.

It is not a de Polignac number, because 8399977621 - 2³ = 8399977613 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 8399977621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8399977601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 599998395 + ... + 599998408.

It is an arithmetic number, because the mean of its divisors is an integer number (2399993608).

Almost surely, 2^8399977621 is an apocalyptic number.

It is an amenable number.

8399977621 is a deficient number, since it is larger than the sum of its proper divisors (1199996811).

8399977621 is a wasteful number, since it uses less digits than its factorization.

8399977621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1199996810.

The product of its digits is 10287648, while the sum is 61.

The square root of 8399977621 is about 91651.3918115813. The cubic root of 8399977621 is about 2032.7909083952.

The spelling of 8399977621 in words is "eight billion, three hundred ninety-nine million, nine hundred seventy-seven thousand, six hundred twenty-one".