21374331761491 has 2 divisors, whose sum is σ = 21374331761492. Its totient is φ = 21374331761490.

The previous prime is 21374331761467. The next prime is 21374331761521. The reversal of 21374331761491 is 19416713347312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21374331761491 - 2⁹ = 21374331760979 is a prime.

It is not a weakly prime, because it can be changed into another prime (21374331761441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10687165880745 + 10687165880746.

It is an arithmetic number, because the mean of its divisors is an integer number (10687165880746).

Almost surely, 2^{21374331761491} is an apocalyptic number.

21374331761491 is a deficient number, since it is larger than the sum of its proper divisors (1).

21374331761491 is an equidigital number, since it uses as much as digits as its factorization.

21374331761491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2286144, while the sum is 52.

The spelling of 21374331761491 in words is "twenty-one trillion, three hundred seventy-four billion, three hundred thirty-one million, seven hundred sixty-one thousand, four hundred ninety-one".