13987391 has 8 divisors (see below), whose sum is σ = 15301200. Its totient is φ = 12680640.

The previous prime is 13987387. The next prime is 13987397. The reversal of 13987391 is 19378931.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 13987391 - 2² = 13987387 is a prime.

It is a super-3 number, since 3×13987391³ (a number of 22 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13987397) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2945 + ... + 6053.

It is an arithmetic number, because the mean of its divisors is an integer number (1912650).

Almost surely, 2^13987391 is an apocalyptic number.

13987391 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

13987391 is a deficient number, since it is larger than the sum of its proper divisors (1313809).

13987391 is a wasteful number, since it uses less digits than its factorization.

13987391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3529.

The product of its digits is 40824, while the sum is 41.

The square root of 13987391 is about 3739.9720587192. The cubic root of 13987391 is about 240.9418487705.

The spelling of 13987391 in words is "thirteen million, nine hundred eighty-seven thousand, three hundred ninety-one".