13878431 has 4 divisors (see below), whose sum is σ = 15861072. Its totient is φ = 11895792.

The previous prime is 13878427. The next prime is 13878439. The reversal of 13878431 is 13487831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13487831 = 7 ⋅1926833.

It is a cyclic number.

It is not a de Polignac number, because 13878431 - 2² = 13878427 is a prime.

It is a super-2 number, since 2×13878431² = 385221694043522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 13878391 and 13878400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13878439) 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, 991310 + ... + 991323.

It is an arithmetic number, because the mean of its divisors is an integer number (3965268).

Almost surely, 2^13878431 is an apocalyptic number.

13878431 is a deficient number, since it is larger than the sum of its proper divisors (1982641).

13878431 is an equidigital number, since it uses as much as digits as its factorization.

13878431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1982640.

The product of its digits is 16128, while the sum is 35.

The square root of 13878431 is about 3725.3766252555. The cubic root of 13878431 is about 240.3145816926.

The spelling of 13878431 in words is "thirteen million, eight hundred seventy-eight thousand, four hundred thirty-one".