1279129921 has 2 divisors, whose sum is σ = 1279129922. Its totient is φ = 1279129920.

The previous prime is 1279129877. The next prime is 1279129961. The reversal of 1279129921 is 1299219721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1250400321 + 28729600 = 35361^2 + 5360^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1279129921 is a prime.

It is not a weakly prime, because it can be changed into another prime (1279129961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639564960 + 639564961.

It is an arithmetic number, because the mean of its divisors is an integer number (639564961).

Almost surely, 2^1279129921 is an apocalyptic number.

It is an amenable number.

1279129921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1279129921 is an equidigital number, since it uses as much as digits as its factorization.

1279129921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40824, while the sum is 43.

The square root of 1279129921 is about 35764.9258492171. The cubic root of 1279129921 is about 1085.5209744398.

The spelling of 1279129921 in words is "one billion, two hundred seventy-nine million, one hundred twenty-nine thousand, nine hundred twenty-one".