1438287891 has 4 divisors (see below), whose sum is σ = 1917717192. Its totient is φ = 958858592.

The previous prime is 1438287883. The next prime is 1438287923. The reversal of 1438287891 is 1987828341.

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 1438287891 - 2³ = 1438287883 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1438287841) 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, 239714646 + ... + 239714651.

It is an arithmetic number, because the mean of its divisors is an integer number (479429298).

Almost surely, 2^1438287891 is an apocalyptic number.

1438287891 is a deficient number, since it is larger than the sum of its proper divisors (479429301).

1438287891 is an equidigital number, since it uses as much as digits as its factorization.

1438287891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 479429300.

The product of its digits is 774144, while the sum is 51.

The square root of 1438287891 is about 37924.7661957197. The cubic root of 1438287891 is about 1128.7955137649.

The spelling of 1438287891 in words is "one billion, four hundred thirty-eight million, two hundred eighty-seven thousand, eight hundred ninety-one".