21541111399 has 2 divisors, whose sum is σ = 21541111400. Its totient is φ = 21541111398.

The previous prime is 21541111387. The next prime is 21541111441. The reversal of 21541111399 is 99311114512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21541111399 - 2²¹ = 21539014247 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21541111369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10770555699 + 10770555700.

It is an arithmetic number, because the mean of its divisors is an integer number (10770555700).

Almost surely, 2^21541111399 is an apocalyptic number.

21541111399 is a deficient number, since it is larger than the sum of its proper divisors (1).

21541111399 is an equidigital number, since it uses as much as digits as its factorization.

21541111399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9720, while the sum is 37.

The spelling of 21541111399 in words is "twenty-one billion, five hundred forty-one million, one hundred eleven thousand, three hundred ninety-nine".