393845640121 has 2 divisors, whose sum is σ = 393845640122. Its totient is φ = 393845640120.

The previous prime is 393845640113. The next prime is 393845640127. The reversal of 393845640121 is 121046548393.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 299559182400 + 94286457721 = 547320^2 + 307061^2 .

It is a cyclic number.

It is not a de Polignac number, because 393845640121 - 2³ = 393845640113 is a prime.

It is a super-2 number, since 2×393845640121² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (393845640127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 196922820060 + 196922820061.

It is an arithmetic number, because the mean of its divisors is an integer number (196922820061).

Almost surely, 2^393845640121 is an apocalyptic number.

It is an amenable number.

393845640121 is a deficient number, since it is larger than the sum of its proper divisors (1).

393845640121 is an equidigital number, since it uses as much as digits as its factorization.

393845640121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 622080, while the sum is 46.

The spelling of 393845640121 in words is "three hundred ninety-three billion, eight hundred forty-five million, six hundred forty thousand, one hundred twenty-one".