21935393891 has 2 divisors, whose sum is σ = 21935393892. Its totient is φ = 21935393890.

The previous prime is 21935393863. The next prime is 21935393911. The reversal of 21935393891 is 19839353912.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21935393891 - 2¹⁰ = 21935392867 is a prime.

It is not a weakly prime, because it can be changed into another prime (21935399891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10967696945 + 10967696946.

It is an arithmetic number, because the mean of its divisors is an integer number (10967696946).

Almost surely, 2^21935393891 is an apocalyptic number.

21935393891 is a deficient number, since it is larger than the sum of its proper divisors (1).

21935393891 is an equidigital number, since it uses as much as digits as its factorization.

21935393891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1574640, while the sum is 53.

The spelling of 21935393891 in words is "twenty-one billion, nine hundred thirty-five million, three hundred ninety-three thousand, eight hundred ninety-one".