1276643764 has 24 divisors (see below), whose sum is σ = 2580596928. Its totient is φ = 546157440.

The previous prime is 1276643761. The next prime is 1276643779. The reversal of 1276643764 is 4673466721.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1276643761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 852624 + ... + 854119.

It is an arithmetic number, because the mean of its divisors is an integer number (107524872).

Almost surely, 2^1276643764 is an apocalyptic number.

It is an amenable number.

1276643764 is an abundant number, since it is smaller than the sum of its proper divisors (1303953164).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1276643764 is a wasteful number, since it uses less digits than its factorization.

1276643764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1706775 (or 1706773 counting only the distinct ones).

The product of its digits is 1016064, while the sum is 46.

The square root of 1276643764 is about 35730.1520287838. The cubic root of 1276643764 is about 1084.8172341108.

The spelling of 1276643764 in words is "one billion, two hundred seventy-six million, six hundred forty-three thousand, seven hundred sixty-four".