1299172661 has 2 divisors, whose sum is σ = 1299172662. Its totient is φ = 1299172660.

The previous prime is 1299172643. The next prime is 1299172663. The reversal of 1299172661 is 1662719921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1020483025 + 278689636 = 31945^2 + 16694^2 .

It is a cyclic number.

It is not a de Polignac number, because 1299172661 - 2³⁰ = 225430837 is a prime.

Together with 1299172663, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1299172663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 649586330 + 649586331.

It is an arithmetic number, because the mean of its divisors is an integer number (649586331).

Almost surely, 2^1299172661 is an apocalyptic number.

It is an amenable number.

1299172661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1299172661 is an equidigital number, since it uses as much as digits as its factorization.

1299172661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 44.

The square root of 1299172661 is about 36044.0378010012. The cubic root of 1299172661 is about 1091.1613078009.

The spelling of 1299172661 in words is "one billion, two hundred ninety-nine million, one hundred seventy-two thousand, six hundred sixty-one".