396896821 has 2 divisors, whose sum is σ = 396896822. Its totient is φ = 396896820.

The previous prime is 396896803. The next prime is 396896831. The reversal of 396896821 is 128698693.

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., 396447921 + 448900 = 19911^2 + 670^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-396896821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (396896831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 198448410 + 198448411.

It is an arithmetic number, because the mean of its divisors is an integer number (198448411).

Almost surely, 2^396896821 is an apocalyptic number.

It is an amenable number.

396896821 is a deficient number, since it is larger than the sum of its proper divisors (1).

396896821 is an equidigital number, since it uses as much as digits as its factorization.

396896821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1119744, while the sum is 52.

The square root of 396896821 is about 19922.2694741337. The cubic root of 396896821 is about 734.8959829355.

The spelling of 396896821 in words is "three hundred ninety-six million, eight hundred ninety-six thousand, eight hundred twenty-one".