1276390138 has 4 divisors (see below), whose sum is σ = 1914585210. Its totient is φ = 638195068.

The previous prime is 1276390127. The next prime is 1276390177. The reversal of 1276390138 is 8310936721.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 816416329 + 459973809 = 28573^2 + 21447^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1276390138.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319097533 + ... + 319097536.

Almost surely, 2^1276390138 is an apocalyptic number.

1276390138 is a deficient number, since it is larger than the sum of its proper divisors (638195072).

1276390138 is an equidigital number, since it uses as much as digits as its factorization.

1276390138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 638195071.

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 1276390138 is about 35726.6026652409. The cubic root of 1276390138 is about 1084.7453905039.

The spelling of 1276390138 in words is "one billion, two hundred seventy-six million, three hundred ninety thousand, one hundred thirty-eight".