16387813 has 16 divisors (see below), whose sum is σ = 19338480. Its totient is φ = 13741056.

The previous prime is 16387807. The next prime is 16387829. The reversal of 16387813 is 31878361.

16387813 = 2862² + 2863².

It can be written as a sum of positive squares in 8 ways, for example, as 82369 + 16305444 = 287^2 + 4038^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16387813 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 (16387853) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5131 + ... + 7687.

It is an arithmetic number, because the mean of its divisors is an integer number (1208655).

Almost surely, 2^16387813 is an apocalyptic number.

16387813 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

16387813 is the 2863-rd centered square number.

It is an amenable number.

16387813 is a deficient number, since it is larger than the sum of its proper divisors (2950667).

16387813 is a wasteful number, since it uses less digits than its factorization.

16387813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2616.

The product of its digits is 24192, while the sum is 37.

The square root of 16387813 is about 4048.1863840490. The cubic root of 16387813 is about 254.0038697821.

The spelling of 16387813 in words is "sixteen million, three hundred eighty-seven thousand, eight hundred thirteen".