1279500661 has 2 divisors, whose sum is σ = 1279500662. Its totient is φ = 1279500660.

The previous prime is 1279500581. The next prime is 1279500683. The reversal of 1279500661 is 1660059721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 980003025 + 299497636 = 31305^2 + 17306^2 .

It is a cyclic number.

It is not a de Polignac number, because 1279500661 - 2¹³ = 1279492469 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1279500661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1279506661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639750330 + 639750331.

It is an arithmetic number, because the mean of its divisors is an integer number (639750331).

Almost surely, 2^1279500661 is an apocalyptic number.

It is an amenable number.

1279500661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1279500661 is an equidigital number, since it uses as much as digits as its factorization.

1279500661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22680, while the sum is 37.

The square root of 1279500661 is about 35770.1084845993. The cubic root of 1279500661 is about 1085.6258392557.

The spelling of 1279500661 in words is "one billion, two hundred seventy-nine million, five hundred thousand, six hundred sixty-one".