396256781 has 2 divisors, whose sum is σ = 396256782. Its totient is φ = 396256780.

The previous prime is 396256771. The next prime is 396256789. The reversal of 396256781 is 187652693.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 394379881 + 1876900 = 19859^2 + 1370^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-396256781 is a prime.

It is a super-2 number, since 2×396256781² = 314038872976963922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (396256789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 198128390 + 198128391.

It is an arithmetic number, because the mean of its divisors is an integer number (198128391).

Almost surely, 2^396256781 is an apocalyptic number.

It is an amenable number.

396256781 is a deficient number, since it is larger than the sum of its proper divisors (1).

396256781 is an equidigital number, since it uses as much as digits as its factorization.

396256781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 544320, while the sum is 47.

The square root of 396256781 is about 19906.1995619455. The cubic root of 396256781 is about 734.5007367287.

The spelling of 396256781 in words is "three hundred ninety-six million, two hundred fifty-six thousand, seven hundred eighty-one".