12571921 has 2 divisors, whose sum is σ = 12571922. Its totient is φ = 12571920.

The previous prime is 12571919. The next prime is 12571943. The reversal of 12571921 is 12917521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10653696 + 1918225 = 3264^2 + 1385^2 .

It is a cyclic number.

It is not a de Polignac number, because 12571921 - 2¹ = 12571919 is a prime.

Together with 12571919, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 12571921.

It is not a weakly prime, because it can be changed into another prime (12571991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6285960 + 6285961.

It is an arithmetic number, because the mean of its divisors is an integer number (6285961).

Almost surely, 2^12571921 is an apocalyptic number.

It is an amenable number.

12571921 is a deficient number, since it is larger than the sum of its proper divisors (1).

12571921 is an equidigital number, since it uses as much as digits as its factorization.

12571921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1260, while the sum is 28.

The square root of 12571921 is about 3545.6904828256. The cubic root of 12571921 is about 232.5236943517.

The spelling of 12571921 in words is "twelve million, five hundred seventy-one thousand, nine hundred twenty-one".