2191397679 has 24 divisors (see below), whose sum is σ = 3271743920. Its totient is φ = 1449607536.

The previous prime is 2191397651. The next prime is 2191397693. The reversal of 2191397679 is 9767931912.

It is a happy number.

2191397679 is a `hidden beast` number, since 2 + 191 + 397 + 67 + 9 = 666.

It is not a de Polignac number, because 2191397679 - 2¹² = 2191393583 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 (2191397629) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3047482 + ... + 3048200.

Almost surely, 2^2191397679 is an apocalyptic number.

2191397679 is a deficient number, since it is larger than the sum of its proper divisors (1080346241).

2191397679 is an frugal number, since it uses more digits than its factorization.

2191397679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1604 (or 879 counting only the distinct ones).

The product of its digits is 1285956, while the sum is 54.

The square root of 2191397679 is about 46812.3667314525. The cubic root of 2191397679 is about 1298.8940651468.

The spelling of 2191397679 in words is "two billion, one hundred ninety-one million, three hundred ninety-seven thousand, six hundred seventy-nine".