1979261191 has 4 divisors (see below), whose sum is σ = 2006374432. Its totient is φ = 1952147952.

The previous prime is 1979261177. The next prime is 1979261197. The reversal of 1979261191 is 1911629791.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1911629791 = 2069 ⋅923939.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1979261191 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 (1979261197) 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, 13556511 + ... + 13556656.

It is an arithmetic number, because the mean of its divisors is an integer number (501593608).

Almost surely, 2^1979261191 is an apocalyptic number.

1979261191 is a deficient number, since it is larger than the sum of its proper divisors (27113241).

1979261191 is an equidigital number, since it uses as much as digits as its factorization.

1979261191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27113240.

The product of its digits is 61236, while the sum is 46.

The square root of 1979261191 is about 44488.8883992396. Note that the first 3 decimals coincide. The cubic root of 1979261191 is about 1255.5510330815.

The spelling of 1979261191 in words is "one billion, nine hundred seventy-nine million, two hundred sixty-one thousand, one hundred ninety-one".