21252171313 has 2 divisors, whose sum is σ = 21252171314. Its totient is φ = 21252171312.

The previous prime is 21252171293. The next prime is 21252171319. The reversal of 21252171313 is 31317125212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16113001969 + 5139169344 = 126937^2 + 71688^2 .

It is a cyclic number.

It is not a de Polignac number, because 21252171313 - 2²¹ = 21250074161 is a prime.

It is not a weakly prime, because it can be changed into another prime (21252171319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10626085656 + 10626085657.

It is an arithmetic number, because the mean of its divisors is an integer number (10626085657).

Almost surely, 2^21252171313 is an apocalyptic number.

It is an amenable number.

21252171313 is a deficient number, since it is larger than the sum of its proper divisors (1).

21252171313 is an equidigital number, since it uses as much as digits as its factorization.

21252171313 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2520, while the sum is 28.

Adding to 21252171313 its reverse (31317125212), we get a palindrome (52569296525).

The spelling of 21252171313 in words is "twenty-one billion, two hundred fifty-two million, one hundred seventy-one thousand, three hundred thirteen".