21016351 has 4 divisors (see below), whose sum is σ = 21026304. Its totient is φ = 21006400.

The previous prime is 21016309. The next prime is 21016381. The reversal of 21016351 is 15361012.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21016351 - 2¹¹ = 21014303 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 (21016381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 415 + ... + 6496.

It is an arithmetic number, because the mean of its divisors is an integer number (5256576).

Almost surely, 2^21016351 is an apocalyptic number.

21016351 is a deficient number, since it is larger than the sum of its proper divisors (9953).

21016351 is an equidigital number, since it uses as much as digits as its factorization.

21016351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9952.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 21016351 is about 4584.3593881806. The cubic root of 21016351 is about 275.9640040923.

Adding to 21016351 its reverse (15361012), we get a palindrome (36377363).

It can be divided in two parts, 210 and 16351, that added together give a palindrome (16561).

The spelling of 21016351 in words is "twenty-one million, sixteen thousand, three hundred fifty-one".