21424312 has 32 divisors (see below), whose sum is σ = 49442400. Its totient is φ = 8475264.

The previous prime is 21424303. The next prime is 21424313. The reversal of 21424312 is 21342412.

It is a super-2 number, since 2×21424312² = 918002289346688, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21424312.

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 polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13987 + ... + 15442.

It is an arithmetic number, because the mean of its divisors is an integer number (1545075).

Almost surely, 2^21424312 is an apocalyptic number.

It is an amenable number.

21424312 is an abundant number, since it is smaller than the sum of its proper divisors (28018088).

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

21424312 is a wasteful number, since it uses less digits than its factorization.

21424312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29455 (or 29451 counting only the distinct ones).

The product of its digits is 384, while the sum is 19.

The square root of 21424312 is about 4628.6404051298. The cubic root of 21424312 is about 277.7382073885.

Adding to 21424312 its reverse (21342412), we get a palindrome (42766724).

It can be divided in two parts, 21424 and 312, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 21424312 in words is "twenty-one million, four hundred twenty-four thousand, three hundred twelve".