21570373813 has 2 divisors, whose sum is σ = 21570373814. Its totient is φ = 21570373812.

The previous prime is 21570373793. The next prime is 21570373817. The reversal of 21570373813 is 31837307512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21562572964 + 7800849 = 146842^2 + 2793^2 .

It is a cyclic number.

It is not a de Polignac number, because 21570373813 - 2⁹ = 21570373301 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21570373817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10785186906 + 10785186907.

It is an arithmetic number, because the mean of its divisors is an integer number (10785186907).

Almost surely, 2^21570373813 is an apocalyptic number.

It is an amenable number.

21570373813 is a deficient number, since it is larger than the sum of its proper divisors (1).

21570373813 is an equidigital number, since it uses as much as digits as its factorization.

21570373813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 105840, while the sum is 40.

The spelling of 21570373813 in words is "twenty-one billion, five hundred seventy million, three hundred seventy-three thousand, eight hundred thirteen".