16318421 has 6 divisors (see below), whose sum is σ = 18982710. Its totient is φ = 13987176.

The previous prime is 16318411. The next prime is 16318459. The reversal of 16318421 is 12481361.

It can be written as a sum of positive squares in only one way, i.e., 16313521 + 4900 = 4039^2 + 70^2 .

It is a de Polignac number, because none of the positive numbers 2^k-16318421 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16318411) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 166466 + ... + 166563.

It is an arithmetic number, because the mean of its divisors is an integer number (3163785).

Almost surely, 2^16318421 is an apocalyptic number.

It is an amenable number.

16318421 is a deficient number, since it is larger than the sum of its proper divisors (2664289).

16318421 is an equidigital number, since it uses as much as digits as its factorization.

16318421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333043 (or 333036 counting only the distinct ones).

The product of its digits is 1152, while the sum is 26.

The square root of 16318421 is about 4039.6065402462. The cubic root of 16318421 is about 253.6448474342.

Adding to 16318421 its reverse (12481361), we get a palindrome (28799782).

The spelling of 16318421 in words is "sixteen million, three hundred eighteen thousand, four hundred twenty-one".