1279999997 has 2 divisors, whose sum is σ = 1279999998. Its totient is φ = 1279999996.

The previous prime is 1279999991. The next prime is 1280000003. The reversal of 1279999997 is 7999999721.

It is a balanced prime because it is at equal distance from previous prime (1279999991) and next prime (1280000003).

It can be written as a sum of positive squares in only one way, i.e., 764301316 + 515698681 = 27646^2 + 22709^2 .

It is a cyclic number.

It is not a de Polignac number, because 1279999997 - 2¹⁴ = 1279983613 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1279999997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1279999991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639999998 + 639999999.

It is an arithmetic number, because the mean of its divisors is an integer number (639999999).

Almost surely, 2^1279999997 is an apocalyptic number.

It is an amenable number.

1279999997 is a deficient number, since it is larger than the sum of its proper divisors (1).

1279999997 is an equidigital number, since it uses as much as digits as its factorization.

1279999997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 52081218, while the sum is 71.

The square root of 1279999997 is about 35777.0875980704. The cubic root of 1279999997 is about 1085.7670457897.

The spelling of 1279999997 in words is "one billion, two hundred seventy-nine million, nine hundred ninety-nine thousand, nine hundred ninety-seven".