1999366491 has 4 divisors (see below), whose sum is σ = 2665821992. Its totient is φ = 1332910992.

The previous prime is 1999366489. The next prime is 1999366493. The reversal of 1999366491 is 1946639991.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1999366489) and next prime (1999366493).

It is not a de Polignac number, because 1999366491 - 2¹ = 1999366489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1999366493) 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, 333227746 + ... + 333227751.

It is an arithmetic number, because the mean of its divisors is an integer number (666455498).

Almost surely, 2^1999366491 is an apocalyptic number.

1999366491 is a deficient number, since it is larger than the sum of its proper divisors (666455501).

1999366491 is an equidigital number, since it uses as much as digits as its factorization.

1999366491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 666455500.

The product of its digits is 2834352, while the sum is 57.

The square root of 1999366491 is about 44714.2761430843. The cubic root of 1999366491 is about 1259.7880072925.

The spelling of 1999366491 in words is "one billion, nine hundred ninety-nine million, three hundred sixty-six thousand, four hundred ninety-one".