991325141621 has 4 divisors (see below), whose sum is σ = 991327158144. Its totient is φ = 991323125100.

The previous prime is 991325141581. The next prime is 991325141629. The reversal of 991325141621 is 126141523199.

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.

It is a cyclic number.

It is not a de Polignac number, because 991325141621 - 2³⁴ = 974145272437 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 (991325141629) 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, 265706 + ... + 1432916.

It is an arithmetic number, because the mean of its divisors is an integer number (247831789536).

Almost surely, 2^991325141621 is an apocalyptic number.

It is an amenable number.

991325141621 is a deficient number, since it is larger than the sum of its proper divisors (2016523).

991325141621 is a wasteful number, since it uses less digits than its factorization.

991325141621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2016522.

The product of its digits is 116640, while the sum is 44.

The spelling of 991325141621 in words is "nine hundred ninety-one billion, three hundred twenty-five million, one hundred forty-one thousand, six hundred twenty-one".