21541158913 has 2 divisors, whose sum is σ = 21541158914. Its totient is φ = 21541158912.

The previous prime is 21541158911. The next prime is 21541158917. The reversal of 21541158913 is 31985114512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18897451024 + 2643707889 = 137468^2 + 51417^2 .

It is a cyclic number.

It is not a de Polignac number, because 21541158913 - 2¹ = 21541158911 is a prime.

Together with 21541158911, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21541158911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10770579456 + 10770579457.

It is an arithmetic number, because the mean of its divisors is an integer number (10770579457).

It is a Proth number, since it is equal to 82173 ⋅ 2¹⁸ + 1 and 82173 < 2¹⁸.

Almost surely, 2^21541158913 is an apocalyptic number.

It is an amenable number.

21541158913 is a deficient number, since it is larger than the sum of its proper divisors (1).

21541158913 is an equidigital number, since it uses as much as digits as its factorization.

21541158913 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43200, while the sum is 40.

The spelling of 21541158913 in words is "twenty-one billion, five hundred forty-one million, one hundred fifty-eight thousand, nine hundred thirteen".