990107921 has 16 divisors (see below), whose sum is σ = 1092287808. Its totient is φ = 889996800.

The previous prime is 990107861. The next prime is 990107927. The reversal of 990107921 is 129701099.

It is not a de Polignac number, because 990107921 - 2²⁶ = 922999057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (990107927) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 766286 + ... + 767576.

It is an arithmetic number, because the mean of its divisors is an integer number (68267988).

Almost surely, 2^990107921 is an apocalyptic number.

It is an amenable number.

990107921 is a deficient number, since it is larger than the sum of its proper divisors (102179887).

990107921 is a wasteful number, since it uses less digits than its factorization.

990107921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2032.

The product of its (nonzero) digits is 10206, while the sum is 38.

The square root of 990107921 is about 31465.9803756374. The cubic root of 990107921 is about 996.6917076043.

It can be divided in two parts, 99010 and 7921, that multiplied together give a triangular number (784258210 = T₃₉₆₀₄).

The spelling of 990107921 in words is "nine hundred ninety million, one hundred seven thousand, nine hundred twenty-one".