990864921 has 8 divisors (see below), whose sum is σ = 1356860224. Its totient is φ = 642723120.

The previous prime is 990864899. The next prime is 990864923. The reversal of 990864921 is 129468099.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 990864921 - 2¹³ = 990856729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (990864923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4463245 + ... + 4463466.

It is an arithmetic number, because the mean of its divisors is an integer number (169607528).

Almost surely, 2^990864921 is an apocalyptic number.

It is an amenable number.

990864921 is a deficient number, since it is larger than the sum of its proper divisors (365995303).

990864921 is a wasteful number, since it uses less digits than its factorization.

990864921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8926751.

The product of its (nonzero) digits is 279936, while the sum is 48.

The square root of 990864921 is about 31478.0069413551. The cubic root of 990864921 is about 996.9456541360.

The spelling of 990864921 in words is "nine hundred ninety million, eight hundred sixty-four thousand, nine hundred twenty-one".