21624342 has 8 divisors (see below), whose sum is σ = 43248696. Its totient is φ = 7208112.

The previous prime is 21624331. The next prime is 21624349. The reversal of 21624342 is 24342612.

It is a sphenic number, since it is the product of 3 distinct primes.

21624342 is an admirable number.

It is a super-2 number, since 2×21624342² = 935224333865928, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21624349) 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, 1802023 + ... + 1802034.

It is an arithmetic number, because the mean of its divisors is an integer number (5406087).

Almost surely, 2^21624342 is an apocalyptic number.

21624342 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21624342 is a wasteful number, since it uses less digits than its factorization.

21624342 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3604062.

The product of its digits is 2304, while the sum is 24.

The square root of 21624342 is about 4650.1980602981. The cubic root of 21624342 is about 278.5999069974.

Adding to 21624342 its reverse (24342612), we get a palindrome (45966954).

The spelling of 21624342 in words is "twenty-one million, six hundred twenty-four thousand, three hundred forty-two".