1276640609 has 4 divisors (see below), whose sum is σ = 1343832240. Its totient is φ = 1209448980.

The previous prime is 1276640597. The next prime is 1276640611. The reversal of 1276640609 is 9060466721.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9060466721 = 64333 ⋅140837.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1276640609 is a prime.

It is a super-2 number, since 2×1276640609² = 3259622489095781762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1276640669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33595787 + ... + 33595824.

It is an arithmetic number, because the mean of its divisors is an integer number (335958060).

Almost surely, 2^1276640609 is an apocalyptic number.

1276640609 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

1276640609 is a deficient number, since it is larger than the sum of its proper divisors (67191631).

1276640609 is an equidigital number, since it uses as much as digits as its factorization.

1276640609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67191630.

The product of its (nonzero) digits is 108864, while the sum is 41.

The square root of 1276640609 is about 35730.1078783706. The cubic root of 1276640609 is about 1084.8163404652.

The spelling of 1276640609 in words is "one billion, two hundred seventy-six million, six hundred forty thousand, six hundred nine".