13707821 has 4 divisors (see below), whose sum is σ = 13843644. Its totient is φ = 13572000.

The previous prime is 13707803. The next prime is 13707829. The reversal of 13707821 is 12870731.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12870731 = 23 ⋅559597.

It can be written as a sum of positive squares in 2 ways, for example, as 5522500 + 8185321 = 2350^2 + 2861^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13707821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13707829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67760 + ... + 67961.

It is an arithmetic number, because the mean of its divisors is an integer number (3460911).

Almost surely, 2^13707821 is an apocalyptic number.

It is an amenable number.

13707821 is a deficient number, since it is larger than the sum of its proper divisors (135823).

13707821 is a wasteful number, since it uses less digits than its factorization.

13707821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135822.

The product of its (nonzero) digits is 2352, while the sum is 29.

The square root of 13707821 is about 3702.4074600184. The cubic root of 13707821 is about 239.3257755200.

The spelling of 13707821 in words is "thirteen million, seven hundred seven thousand, eight hundred twenty-one".