21203416 has 24 divisors (see below), whose sum is σ = 43052580. Its totient is φ = 9785568.

The previous prime is 21203407. The next prime is 21203419. The reversal of 21203416 is 61430212.

It is a junction number, because it is equal to n+sod(n) for n = 21203393 and 21203402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203419) 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 5 ways as a sum of consecutive naturals, for example, 6490 + ... + 9193.

Almost surely, 2^21203416 is an apocalyptic number.

21203416 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21203416 is an abundant number, since it is smaller than the sum of its proper divisors (21849164).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21203416 is a wasteful number, since it uses less digits than its factorization.

21203416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15715 (or 15698 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 21203416 is about 4604.7167122419. The cubic root of 21203416 is about 276.7803651971.

Adding to 21203416 its reverse (61430212), we get a palindrome (82633628).

The spelling of 21203416 in words is "twenty-one million, two hundred three thousand, four hundred sixteen".