397213236221 has 2 divisors, whose sum is σ = 397213236222. Its totient is φ = 397213236220.

The previous prime is 397213236209. The next prime is 397213236269. The reversal of 397213236221 is 122632312793.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 388783425625 + 8429810596 = 623525^2 + 91814^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-397213236221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (397213236281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 198606618110 + 198606618111.

It is an arithmetic number, because the mean of its divisors is an integer number (198606618111).

Almost surely, 2^397213236221 is an apocalyptic number.

It is an amenable number.

397213236221 is a deficient number, since it is larger than the sum of its proper divisors (1).

397213236221 is an equidigital number, since it uses as much as digits as its factorization.

397213236221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 163296, while the sum is 41.

The spelling of 397213236221 in words is "three hundred ninety-seven billion, two hundred thirteen million, two hundred thirty-six thousand, two hundred twenty-one".