1991299 has 4 divisors (see below), whose sum is σ = 2010736. Its totient is φ = 1971864.

The previous prime is 1991293. The next prime is 1991351. The reversal of 1991299 is 9921991.

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

It is a cyclic number.

It is not a de Polignac number, because 1991299 - 2⁵ = 1991267 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991293) 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, 9564 + ... + 9769.

It is an arithmetic number, because the mean of its divisors is an integer number (502684).

2^1991299 is an apocalyptic number.

1991299 is a deficient number, since it is larger than the sum of its proper divisors (19437).

1991299 is a wasteful number, since it uses less digits than its factorization.

1991299 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19436.

The product of its digits is 13122, while the sum is 40.

The square root of 1991299 is about 1411.1339411976. The cubic root of 1991299 is about 125.8091298370.

The spelling of 1991299 in words is "one million, nine hundred ninety-one thousand, two hundred ninety-nine".