1318985638 has 4 divisors (see below), whose sum is σ = 1978478460. Its totient is φ = 659492818.

The previous prime is 1318985609. The next prime is 1318985639. The reversal of 1318985638 is 8365898131.

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

It is a super-2 number, since 2×1318985638² = 3479446226500534088, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1318985639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 329746408 + ... + 329746411.

It is an arithmetic number, because the mean of its divisors is an integer number (494619615).

Almost surely, 2^1318985638 is an apocalyptic number.

1318985638 is a deficient number, since it is larger than the sum of its proper divisors (659492822).

1318985638 is an equidigital number, since it uses as much as digits as its factorization.

1318985638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 659492821.

The product of its digits is 1244160, while the sum is 52.

The square root of 1318985638 is about 36317.8418687014. The cubic root of 1318985638 is about 1096.6802496242.

The spelling of 1318985638 in words is "one billion, three hundred eighteen million, nine hundred eighty-five thousand, six hundred thirty-eight".