21831722879 has 2 divisors, whose sum is σ = 21831722880. Its totient is φ = 21831722878.

The previous prime is 21831722837. The next prime is 21831722911. The reversal of 21831722879 is 97822713812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21831722879 - 2²⁰ = 21830674303 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21831722819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10915861439 + 10915861440.

It is an arithmetic number, because the mean of its divisors is an integer number (10915861440).

Almost surely, 2^21831722879 is an apocalyptic number.

21831722879 is a deficient number, since it is larger than the sum of its proper divisors (1).

21831722879 is an equidigital number, since it uses as much as digits as its factorization.

21831722879 is an evil number, because the sum of its binary digits is even.

The product of its digits is 677376, while the sum is 50.

The spelling of 21831722879 in words is "twenty-one billion, eight hundred thirty-one million, seven hundred twenty-two thousand, eight hundred seventy-nine".