990900001 has 12 divisors (see below), whose sum is σ = 1241348052. Its totient is φ = 784008288.

The previous prime is 990899999. The next prime is 990900019. The reversal of 990900001 is 100009099.

It can be written as a sum of positive squares in 2 ways, for example, as 126540001 + 864360000 = 11249^2 + 29400^2 .

It is not a de Polignac number, because 990900001 - 2¹ = 990899999 is a prime.

It is not an unprimeable number, because it can be changed into a prime (990900061) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 777150 + ... + 778423.

It is an arithmetic number, because the mean of its divisors is an integer number (103445671).

Almost surely, 2^990900001 is an apocalyptic number.

990900001 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

It is an amenable number.

990900001 is a deficient number, since it is larger than the sum of its proper divisors (250448051).

990900001 is a wasteful number, since it uses less digits than its factorization.

990900001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1555600 (or 1555593 counting only the distinct ones).

The product of its (nonzero) digits is 729, while the sum is 28.

The square root of 990900001 is about 31478.5641508630. The cubic root of 990900001 is about 996.9574190901.

The spelling of 990900001 in words is "nine hundred ninety million, nine hundred thousand, one".