1268639 has 4 divisors (see below), whose sum is σ = 1271256. Its totient is φ = 1266024.

The previous prime is 1268633. The next prime is 1268669. The reversal of 1268639 is 9368621.

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

It is a cyclic number.

It is not a de Polignac number, because 1268639 - 2⁴ = 1268623 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1268599 and 1268608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1268633) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 344 + ... + 1629.

It is an arithmetic number, because the mean of its divisors is an integer number (317814).

2^1268639 is an apocalyptic number.

1268639 is a deficient number, since it is larger than the sum of its proper divisors (2617).

1268639 is an equidigital number, since it uses as much as digits as its factorization.

1268639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2616.

The product of its digits is 15552, while the sum is 35.

The square root of 1268639 is about 1126.3387589886. The cubic root of 1268639 is about 108.2545151877.

The spelling of 1268639 in words is "one million, two hundred sixty-eight thousand, six hundred thirty-nine".