21571497293 has 2 divisors, whose sum is σ = 21571497294. Its totient is φ = 21571497292.

The previous prime is 21571497289. The next prime is 21571497307. The reversal of 21571497293 is 39279417512.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19149577924 + 2421919369 = 138382^2 + 49213^2 .

It is a cyclic number.

It is not a de Polignac number, because 21571497293 - 2² = 21571497289 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21571497203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10785748646 + 10785748647.

It is an arithmetic number, because the mean of its divisors is an integer number (10785748647).

Almost surely, 2^21571497293 is an apocalyptic number.

It is an amenable number.

21571497293 is a deficient number, since it is larger than the sum of its proper divisors (1).

21571497293 is an equidigital number, since it uses as much as digits as its factorization.

21571497293 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 952560, while the sum is 50.

The spelling of 21571497293 in words is "twenty-one billion, five hundred seventy-one million, four hundred ninety-seven thousand, two hundred ninety-three".