990215081 has 4 divisors (see below), whose sum is σ = 990314964. Its totient is φ = 990115200.

The previous prime is 990215071. The next prime is 990215123. The reversal of 990215081 is 180512099.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 139617856 + 850597225 = 11816^2 + 29165^2 .

It is a cyclic number.

It is not a de Polignac number, because 990215081 - 2¹⁴ = 990198697 is a prime.

It is a super-2 number, since 2×990215081² = 1961051813279673122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (990215071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33200 + ... + 55521.

It is an arithmetic number, because the mean of its divisors is an integer number (247578741).

Almost surely, 2^990215081 is an apocalyptic number.

It is an amenable number.

990215081 is a deficient number, since it is larger than the sum of its proper divisors (99883).

990215081 is a wasteful number, since it uses less digits than its factorization.

990215081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99882.

The product of its (nonzero) digits is 6480, while the sum is 35.

The square root of 990215081 is about 31467.6831209417. The cubic root of 990215081 is about 996.7276638296.

The spelling of 990215081 in words is "nine hundred ninety million, two hundred fifteen thousand, eighty-one".