21142424 has 32 divisors (see below), whose sum is σ = 42502320. Its totient is φ = 9824256.

The previous prime is 21142423. The next prime is 21142427. The reversal of 21142424 is 42424112.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21142396 and 21142405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21142423) 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 7 ways as a sum of consecutive naturals, for example, 10352 + ... + 12224.

Almost surely, 2^21142424 is an apocalyptic number.

It is an amenable number.

21142424 is an abundant number, since it is smaller than the sum of its proper divisors (21359896).

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

21142424 is a wasteful number, since it uses less digits than its factorization.

21142424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1979 (or 1975 counting only the distinct ones).

The product of its digits is 512, while the sum is 20.

The square root of 21142424 is about 4598.0891683394. The cubic root of 21142424 is about 276.5147224584.

Adding to 21142424 its reverse (42424112), we get a palindrome (63566536).

The spelling of 21142424 in words is "twenty-one million, one hundred forty-two thousand, four hundred twenty-four".