989945442475421 has 2 divisors, whose sum is σ = 989945442475422. Its totient is φ = 989945442475420.

The previous prime is 989945442475349. The next prime is 989945442475607. The reversal of 989945442475421 is 124574244549989.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 503660868912100 + 486284573563321 = 22442390^2 + 22051861^2 .

It is a cyclic number.

It is not a de Polignac number, because 989945442475421 - 2³⁴ = 989928262606237 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (989945442472421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494972721237710 + 494972721237711.

It is an arithmetic number, because the mean of its divisors is an integer number (494972721237711).

Almost surely, 2^{989945442475421} is an apocalyptic number.

It is an amenable number.

989945442475421 is a deficient number, since it is larger than the sum of its proper divisors (1).

989945442475421 is an equidigital number, since it uses as much as digits as its factorization.

989945442475421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4180377600, while the sum is 77.

The spelling of 989945442475421 in words is "nine hundred eighty-nine trillion, nine hundred forty-five billion, four hundred forty-two million, four hundred seventy-five thousand, four hundred twenty-one".