1376721261 has 12 divisors (see below), whose sum is σ = 2021198140. Its totient is φ = 902767680.

The previous prime is 1376721259. The next prime is 1376721299. The reversal of 1376721261 is 1621276731.

It is a happy number.

1376721261 is a `hidden beast` number, since 1 + 376 + 7 + 21 + 261 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 188540361 + 1188180900 = 13731^2 + 34470^2 .

It is not a de Polignac number, because 1376721261 - 2¹ = 1376721259 is a prime.

It is a super-2 number, since 2×1376721261² = 3790722860978860242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1376721461) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1253296 + ... + 1254393.

Almost surely, 2^1376721261 is an apocalyptic number.

It is an amenable number.

1376721261 is a deficient number, since it is larger than the sum of its proper divisors (644476879).

1376721261 is a wasteful number, since it uses less digits than its factorization.

1376721261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2507756 (or 2507753 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The square root of 1376721261 is about 37104.1946550521. The cubic root of 1376721261 is about 1112.4538578851.

Adding to 1376721261 its reverse (1621276731), we get a palindrome (2997997992).

The spelling of 1376721261 in words is "one billion, three hundred seventy-six million, seven hundred twenty-one thousand, two hundred sixty-one".