11997461891 has 4 divisors (see below), whose sum is σ = 11998389384. Its totient is φ = 11996534400.

The previous prime is 11997461881. The next prime is 11997461893. The reversal of 11997461891 is 19816479911.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19816479911 = 631 ⋅31404881.

It is a cyclic number.

It is not a de Polignac number, because 11997461891 - 2¹⁴ = 11997445507 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11997461893) 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, 444065 + ... + 470306.

It is an arithmetic number, because the mean of its divisors is an integer number (2999597346).

Almost surely, 2^11997461891 is an apocalyptic number.

11997461891 is a deficient number, since it is larger than the sum of its proper divisors (927493).

11997461891 is an equidigital number, since it uses as much as digits as its factorization.

11997461891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 927492.

The product of its digits is 979776, while the sum is 56.

The spelling of 11997461891 in words is "eleven billion, nine hundred ninety-seven million, four hundred sixty-one thousand, eight hundred ninety-one".