23421121991 has 2 divisors, whose sum is σ = 23421121992. Its totient is φ = 23421121990.

The previous prime is 23421121981. The next prime is 23421122009. The reversal of 23421121991 is 19912112432.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 23421121991 - 2¹⁴ = 23421105607 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23421121931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11710560995 + 11710560996.

It is an arithmetic number, because the mean of its divisors is an integer number (11710560996).

Almost surely, 2^23421121991 is an apocalyptic number.

23421121991 is a deficient number, since it is larger than the sum of its proper divisors (1).

23421121991 is an equidigital number, since it uses as much as digits as its factorization.

23421121991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 35.

The spelling of 23421121991 in words is "twenty-three billion, four hundred twenty-one million, one hundred twenty-one thousand, nine hundred ninety-one".