21149056493 has 2 divisors, whose sum is σ = 21149056494. Its totient is φ = 21149056492.

The previous prime is 21149056457. The next prime is 21149056501. The reversal of 21149056493 is 39465094112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11506209289 + 9642847204 = 107267^2 + 98198^2 .

It is a cyclic number.

It is not a de Polignac number, because 21149056493 - 2²⁴ = 21132279277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21149056793) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10574528246 + 10574528247.

It is an arithmetic number, because the mean of its divisors is an integer number (10574528247).

Almost surely, 2^21149056493 is an apocalyptic number.

It is an amenable number.

21149056493 is a deficient number, since it is larger than the sum of its proper divisors (1).

21149056493 is an equidigital number, since it uses as much as digits as its factorization.

21149056493 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 233280, while the sum is 44.

The spelling of 21149056493 in words is "twenty-one billion, one hundred forty-nine million, fifty-six thousand, four hundred ninety-three".