21372774728191 has 2 divisors, whose sum is σ = 21372774728192. Its totient is φ = 21372774728190.

The previous prime is 21372774728099. The next prime is 21372774728267. The reversal of 21372774728191 is 19182747727312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21372774728191 - 2⁹ = 21372774727679 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21372774798191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10686387364095 + 10686387364096.

It is an arithmetic number, because the mean of its divisors is an integer number (10686387364096).

Almost surely, 2^{21372774728191} is an apocalyptic number.

21372774728191 is a deficient number, since it is larger than the sum of its proper divisors (1).

21372774728191 is an equidigital number, since it uses as much as digits as its factorization.

21372774728191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16595712, while the sum is 61.

The spelling of 21372774728191 in words is "twenty-one trillion, three hundred seventy-two billion, seven hundred seventy-four million, seven hundred twenty-eight thousand, one hundred ninety-one".