21513540334991 has 2 divisors, whose sum is σ = 21513540334992. Its totient is φ = 21513540334990.

The previous prime is 21513540334943. The next prime is 21513540335117. The reversal of 21513540334991 is 19943304531512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21513540334991 - 2²² = 21513536140687 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21513540334901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10756770167495 + 10756770167496.

It is an arithmetic number, because the mean of its divisors is an integer number (10756770167496).

Almost surely, 2^{21513540334991} is an apocalyptic number.

21513540334991 is a deficient number, since it is larger than the sum of its proper divisors (1).

21513540334991 is an equidigital number, since it uses as much as digits as its factorization.

21513540334991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1749600, while the sum is 50.

The spelling of 21513540334991 in words is "twenty-one trillion, five hundred thirteen billion, five hundred forty million, three hundred thirty-four thousand, nine hundred ninety-one".