1276639997 has 2 divisors, whose sum is σ = 1276639998. Its totient is φ = 1276639996.

The previous prime is 1276639967. The next prime is 1276640003. The reversal of 1276639997 is 7999366721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1205895076 + 70744921 = 34726^2 + 8411^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1276639997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1276639967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 638319998 + 638319999.

It is an arithmetic number, because the mean of its divisors is an integer number (638319999).

Almost surely, 2^1276639997 is an apocalyptic number.

It is an amenable number.

1276639997 is a deficient number, since it is larger than the sum of its proper divisors (1).

1276639997 is an equidigital number, since it uses as much as digits as its factorization.

1276639997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7715736, while the sum is 59.

The square root of 1276639997 is about 35730.0993141637. The cubic root of 1276639997 is about 1084.8161671176.

The spelling of 1276639997 in words is "one billion, two hundred seventy-six million, six hundred thirty-nine thousand, nine hundred ninety-seven".