13872781 has 4 divisors (see below), whose sum is σ = 14939932. Its totient is φ = 12805632.

The previous prime is 13872773. The next prime is 13872787. The reversal of 13872781 is 18727831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18727831 = 821 ⋅22811.

It can be written as a sum of positive squares in 2 ways, for example, as 4447881 + 9424900 = 2109^2 + 3070^2 .

It is a cyclic number.

It is not a de Polignac number, because 13872781 - 2³ = 13872773 is a prime.

It is a super-2 number, since 2×13872781² = 384908105347922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 13872781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13872787) 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, 533556 + ... + 533581.

It is an arithmetic number, because the mean of its divisors is an integer number (3734983).

Almost surely, 2^13872781 is an apocalyptic number.

It is an amenable number.

13872781 is a deficient number, since it is larger than the sum of its proper divisors (1067151).

13872781 is a wasteful number, since it uses less digits than its factorization.

13872781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1067150.

The product of its digits is 18816, while the sum is 37.

The square root of 13872781 is about 3724.6182354706. The cubic root of 13872781 is about 240.2819660537.

The spelling of 13872781 in words is "thirteen million, eight hundred seventy-two thousand, seven hundred eighty-one".