8444891720421 has 64 divisors (see below), whose sum is σ = 13788265881600. Its totient is φ = 5075836083648.

The previous prime is 8444891720341. The next prime is 8444891720423. The reversal of 8444891720421 is 1240271984448.

8444891720421 is a `hidden beast` number, since 8 + 4 + 4 + 48 + 9 + 172 + 0 + 421 = 666.

It is not a de Polignac number, because 8444891720421 - 2¹⁷ = 8444891589349 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8444891720423) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 7508470 + ... + 8559608.

It is an arithmetic number, because the mean of its divisors is an integer number (215441654400).

Almost surely, 2^{8444891720421} is an apocalyptic number.

It is an amenable number.

8444891720421 is a deficient number, since it is larger than the sum of its proper divisors (5343374161179).

8444891720421 is a wasteful number, since it uses less digits than its factorization.

8444891720421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1051695 (or 1051689 counting only the distinct ones).

The product of its (nonzero) digits is 4128768, while the sum is 54.

The spelling of 8444891720421 in words is "eight trillion, four hundred forty-four billion, eight hundred ninety-one million, seven hundred twenty thousand, four hundred twenty-one".