13973781 has 4 divisors (see below), whose sum is σ = 18631712. Its totient is φ = 9315852.

The previous prime is 13973767. The next prime is 13973789. The reversal of 13973781 is 18737931.

It is a happy number.

13973781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 13973781 - 2⁵ = 13973749 is a prime.

It is a super-2 number, since 2×13973781² = 390533110871922, which contains 22 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 (13973789) 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, 2328961 + ... + 2328966.

It is an arithmetic number, because the mean of its divisors is an integer number (4657928).

Almost surely, 2^13973781 is an apocalyptic number.

It is an amenable number.

13973781 is a deficient number, since it is larger than the sum of its proper divisors (4657931).

13973781 is an equidigital number, since it uses as much as digits as its factorization.

13973781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4657930.

The product of its digits is 31752, while the sum is 39.

The square root of 13973781 is about 3738.1520835835. The cubic root of 13973781 is about 240.8636763957.

It can be divided in two parts, 139 and 73781, that added together give a triangular number (73920 = T₃₈₄).

The spelling of 13973781 in words is "thirteen million, nine hundred seventy-three thousand, seven hundred eighty-one".