990742421 has 4 divisors (see below), whose sum is σ = 991452000. Its totient is φ = 990032844.

The previous prime is 990742387. The next prime is 990742427. The reversal of 990742421 is 124247099.

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 990742421 - 2¹⁸ = 990480277 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 (990742427) 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, 352691 + ... + 355488.

It is an arithmetic number, because the mean of its divisors is an integer number (247863000).

Almost surely, 2^990742421 is an apocalyptic number.

It is an amenable number.

990742421 is a deficient number, since it is larger than the sum of its proper divisors (709579).

990742421 is a wasteful number, since it uses less digits than its factorization.

990742421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 709578.

The product of its (nonzero) digits is 36288, while the sum is 38.

The square root of 990742421 is about 31476.0610782226. The cubic root of 990742421 is about 996.9045685238.

The spelling of 990742421 in words is "nine hundred ninety million, seven hundred forty-two thousand, four hundred twenty-one".