13773721 has 4 divisors (see below), whose sum is σ = 14833252. Its totient is φ = 12714192.

The previous prime is 13773719. The next prime is 13773737. The reversal of 13773721 is 12737731.

13773721 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 an emirpimes, since its reverse is a distinct semiprime: 12737731 = 37 ⋅344263.

It can be written as a sum of positive squares in 2 ways, for example, as 9211225 + 4562496 = 3035^2 + 2136^2 .

It is a cyclic number.

It is not a de Polignac number, because 13773721 - 2¹ = 13773719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13773701) 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, 529746 + ... + 529771.

It is an arithmetic number, because the mean of its divisors is an integer number (3708313).

Almost surely, 2^13773721 is an apocalyptic number.

It is an amenable number.

13773721 is a deficient number, since it is larger than the sum of its proper divisors (1059531).

13773721 is a wasteful number, since it uses less digits than its factorization.

13773721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1059530.

The product of its digits is 6174, while the sum is 31.

The square root of 13773721 is about 3711.2964042232. The cubic root of 13773721 is about 239.7086800942.

The spelling of 13773721 in words is "thirteen million, seven hundred seventy-three thousand, seven hundred twenty-one".