990198019901 has 16 divisors (see below), whose sum is σ = 1011410817648. Its totient is φ = 969196492800.

The previous prime is 990198019819. The next prime is 990198019969. The reversal of 990198019901 is 109910891099.

It can be written as a sum of positive squares in 8 ways, for example, as 10583059876 + 979614960025 = 102874^2 + 989755^2 .

It is a cyclic number.

It is not a de Polignac number, because 990198019901 - 2¹⁰ = 990198018877 is a prime.

It is a super-2 number, since 2×990198019901² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (990198019991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35399561 + ... + 35427521.

It is an arithmetic number, because the mean of its divisors is an integer number (63213176103).

Almost surely, 2^990198019901 is an apocalyptic number.

It is an amenable number.

990198019901 is a deficient number, since it is larger than the sum of its proper divisors (21212797747).

990198019901 is a wasteful number, since it uses less digits than its factorization.

990198019901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31712.

The product of its (nonzero) digits is 472392, while the sum is 56.

It can be divided in two parts, 990 and 198019901, that added together give a palindrome (198020891).

The spelling of 990198019901 in words is "nine hundred ninety billion, one hundred ninety-eight million, nineteen thousand, nine hundred one".