21424316 has 24 divisors (see below), whose sum is σ = 39795840. Its totient is φ = 10070192.

The previous prime is 21424313. The next prime is 21424327. The reversal of 21424316 is 61342412.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a junction number, because it is equal to n+sod(n) for n = 21424291 and 21424300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21424313) 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 7 ways as a sum of consecutive naturals, for example, 3455 + ... + 7401.

It is an arithmetic number, because the mean of its divisors is an integer number (1658160).

Almost surely, 2^21424316 is an apocalyptic number.

It is an amenable number.

21424316 is a deficient number, since it is larger than the sum of its proper divisors (18371524).

21424316 is a wasteful number, since it uses less digits than its factorization.

21424316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4033 (or 4031 counting only the distinct ones).

The product of its digits is 1152, while the sum is 23.

The square root of 21424316 is about 4628.6408372221. The cubic root of 21424316 is about 277.7382246734.

Adding to 21424316 its reverse (61342412), we get a palindrome (82766728).

The spelling of 21424316 in words is "twenty-one million, four hundred twenty-four thousand, three hundred sixteen".