1276387421 has 4 divisors (see below), whose sum is σ = 1351469052. Its totient is φ = 1201305792.

The previous prime is 1276387417. The next prime is 1276387429. The reversal of 1276387421 is 1247836721.

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

It can be written as a sum of positive squares in 2 ways, for example, as 668222500 + 608164921 = 25850^2 + 24661^2 .

It is a cyclic number.

It is not a de Polignac number, because 1276387421 - 2² = 1276387417 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1276387429) 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 3 ways as a sum of consecutive naturals, for example, 37540790 + ... + 37540823.

It is an arithmetic number, because the mean of its divisors is an integer number (337867263).

Almost surely, 2^1276387421 is an apocalyptic number.

It is an amenable number.

1276387421 is a deficient number, since it is larger than the sum of its proper divisors (75081631).

1276387421 is an equidigital number, since it uses as much as digits as its factorization.

1276387421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75081630.

The product of its digits is 112896, while the sum is 41.

The square root of 1276387421 is about 35726.5646403345. The cubic root of 1276387421 is about 1084.7446208188.

The spelling of 1276387421 in words is "one billion, two hundred seventy-six million, three hundred eighty-seven thousand, four hundred twenty-one".