21008024 has 8 divisors (see below), whose sum is σ = 39390060. Its totient is φ = 10504008.

The previous prime is 21008023. The next prime is 21008027. The reversal of 21008024 is 42080012.

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 21007993 and 21008011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21008021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1312994 + ... + 1313009.

Almost surely, 2^21008024 is an apocalyptic number.

It is an amenable number.

21008024 is a deficient number, since it is larger than the sum of its proper divisors (18382036).

21008024 is a wasteful number, since it uses less digits than its factorization.

21008024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2626009 (or 2626005 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 21008024 is about 4583.4511015173. The cubic root of 21008024 is about 275.9275522232.

Adding to 21008024 its reverse (42080012), we get a palindrome (63088036).

The spelling of 21008024 in words is "twenty-one million, eight thousand, twenty-four".