11997461921 has 2 divisors, whose sum is σ = 11997461922. Its totient is φ = 11997461920.

The previous prime is 11997461893. The next prime is 11997461941. The reversal of 11997461921 is 12916479911.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6697621921 + 5299840000 = 81839^2 + 72800^2 .

It is a cyclic number.

It is not a de Polignac number, because 11997461921 - 2¹⁰ = 11997460897 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 11997461921.

It is not a weakly prime, because it can be changed into another prime (11997461941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5998730960 + 5998730961.

It is an arithmetic number, because the mean of its divisors is an integer number (5998730961).

Almost surely, 2^11997461921 is an apocalyptic number.

It is an amenable number.

11997461921 is a deficient number, since it is larger than the sum of its proper divisors (1).

11997461921 is an equidigital number, since it uses as much as digits as its factorization.

11997461921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 244944, while the sum is 50.

The spelling of 11997461921 in words is "eleven billion, nine hundred ninety-seven million, four hundred sixty-one thousand, nine hundred twenty-one".