1276138781 has 8 divisors (see below), whose sum is σ = 1343633280. Its totient is φ = 1208677248.

The previous prime is 1276138771. The next prime is 1276138889. The reversal of 1276138781 is 1878316721.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1276138781 - 2¹⁰ = 1276137757 is a prime.

It is a super-2 number, since 2×1276138781² = 3257060376744331922, 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 (1276138741) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 137180 + ... + 146186.

It is an arithmetic number, because the mean of its divisors is an integer number (167954160).

Almost surely, 2^1276138781 is an apocalyptic number.

It is an amenable number.

1276138781 is a deficient number, since it is larger than the sum of its proper divisors (67494499).

1276138781 is an equidigital number, since it uses as much as digits as its factorization.

1276138781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16483.

The product of its digits is 112896, while the sum is 44.

The square root of 1276138781 is about 35723.0847072310. The cubic root of 1276138781 is about 1084.6741802370.

The spelling of 1276138781 in words is "one billion, two hundred seventy-six million, one hundred thirty-eight thousand, seven hundred eighty-one".