21823131991487 has 2 divisors, whose sum is σ = 21823131991488. Its totient is φ = 21823131991486.

The previous prime is 21823131991459. The next prime is 21823131991547. The reversal of 21823131991487 is 78419913132812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21823131991487 - 2²⁰ = 21823130942911 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21823131991447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10911565995743 + 10911565995744.

It is an arithmetic number, because the mean of its divisors is an integer number (10911565995744).

Almost surely, 2^{21823131991487} is an apocalyptic number.

21823131991487 is a deficient number, since it is larger than the sum of its proper divisors (1).

21823131991487 is an equidigital number, since it uses as much as digits as its factorization.

21823131991487 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5225472, while the sum is 59.

The spelling of 21823131991487 in words is "twenty-one trillion, eight hundred twenty-three billion, one hundred thirty-one million, nine hundred ninety-one thousand, four hundred eighty-seven".