1278631 has 2 divisors, whose sum is σ = 1278632. Its totient is φ = 1278630.

The previous prime is 1278623. The next prime is 1278637. The reversal of 1278631 is 1368721.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1278631 - 2³ = 1278623 is a prime.

It is a super-2 number, since 2×1278631² = 3269794468322, which contains 22 as substring.

It is a Chen prime.

1278631 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1278631.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1278637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639315 + 639316.

It is an arithmetic number, because the mean of its divisors is an integer number (639316).

2^1278631 is an apocalyptic number.

1278631 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278631 is an equidigital number, since it uses as much as digits as its factorization.

1278631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2016, while the sum is 28.

The square root of 1278631 is about 1130.7656698008. The cubic root of 1278631 is about 108.5379821293.

The spelling of 1278631 in words is "one million, two hundred seventy-eight thousand, six hundred thirty-one".