21120993791 has 2 divisors, whose sum is σ = 21120993792. Its totient is φ = 21120993790.

The previous prime is 21120993767. The next prime is 21120993833. The reversal of 21120993791 is 19739902112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21120993791 - 2²⁶ = 21053884927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21120996791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560496895 + 10560496896.

It is an arithmetic number, because the mean of its divisors is an integer number (10560496896).

Almost surely, 2^21120993791 is an apocalyptic number.

21120993791 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120993791 is an equidigital number, since it uses as much as digits as its factorization.

21120993791 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 61236, while the sum is 44.

The spelling of 21120993791 in words is "twenty-one billion, one hundred twenty million, nine hundred ninety-three thousand, seven hundred ninety-one".