1990216915 has 4 divisors (see below), whose sum is σ = 2388260304. Its totient is φ = 1592173528.

The previous prime is 1990216913. The next prime is 1990216919. The reversal of 1990216915 is 5196120991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5196120991 = 557 ⋅9328763.

It is a cyclic number.

It is not a de Polignac number, because 1990216915 - 2¹ = 1990216913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1990216913) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 199021687 + ... + 199021696.

It is an arithmetic number, because the mean of its divisors is an integer number (597065076).

Almost surely, 2^1990216915 is an apocalyptic number.

1990216915 is a deficient number, since it is larger than the sum of its proper divisors (398043389).

1990216915 is an equidigital number, since it uses as much as digits as its factorization.

1990216915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398043388.

The product of its (nonzero) digits is 43740, while the sum is 43.

The square root of 1990216915 is about 44611.8472493574. The cubic root of 1990216915 is about 1257.8633720453.

The spelling of 1990216915 in words is "one billion, nine hundred ninety million, two hundred sixteen thousand, nine hundred fifteen".