1273666621 has 2 divisors, whose sum is σ = 1273666622. Its totient is φ = 1273666620.

The previous prime is 1273666613. The next prime is 1273666643. The reversal of 1273666621 is 1266663721.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1054300900 + 219365721 = 32470^2 + 14811^2 .

It is a cyclic number.

It is not a de Polignac number, because 1273666621 - 2³ = 1273666613 is a prime.

It is a super-2 number, since 2×1273666621² = 3244453322899115282, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1273666421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 636833310 + 636833311.

It is an arithmetic number, because the mean of its divisors is an integer number (636833311).

Almost surely, 2^1273666621 is an apocalyptic number.

It is an amenable number.

1273666621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1273666621 is an equidigital number, since it uses as much as digits as its factorization.

1273666621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108864, while the sum is 40.

The square root of 1273666621 is about 35688.4662180935. The cubic root of 1273666621 is about 1083.9733104021.

The spelling of 1273666621 in words is "one billion, two hundred seventy-three million, six hundred sixty-six thousand, six hundred twenty-one".