1991679853 has 4 divisors (see below), whose sum is σ = 2006883648. Its totient is φ = 1976476060.

The previous prime is 1991679841. The next prime is 1991679857. The reversal of 1991679853 is 3589761991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1991679853 - 2¹⁷ = 1991548781 is a prime.

It is a super-2 number, since 2×1991679853² = 7933577273692203218, which 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 (1991679857) 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, 7601701 + ... + 7601962.

It is an arithmetic number, because the mean of its divisors is an integer number (501720912).

Almost surely, 2^1991679853 is an apocalyptic number.

It is an amenable number.

1991679853 is a deficient number, since it is larger than the sum of its proper divisors (15203795).

1991679853 is a wasteful number, since it uses less digits than its factorization.

1991679853 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15203794.

The product of its digits is 3674160, while the sum is 58.

The square root of 1991679853 is about 44628.2405322011. The cubic root of 1991679853 is about 1258.1715001716.

The spelling of 1991679853 in words is "one billion, nine hundred ninety-one million, six hundred seventy-nine thousand, eight hundred fifty-three".