21024621 has 24 divisors (see below), whose sum is σ = 32841120. Its totient is φ = 12915936.

The previous prime is 21024617. The next prime is 21024629. The reversal of 21024621 is 12642012.

21024621 is a `hidden beast` number, since 21 + 0 + 24 + 621 = 666.

It is not a de Polignac number, because 21024621 - 2² = 21024617 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21024594 and 21024603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21024629) 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 23 ways as a sum of consecutive naturals, for example, 4666 + ... + 7988.

It is an arithmetic number, because the mean of its divisors is an integer number (1368380).

Almost surely, 2^21024621 is an apocalyptic number.

It is an amenable number.

21024621 is a deficient number, since it is larger than the sum of its proper divisors (11816499).

21024621 is a wasteful number, since it uses less digits than its factorization.

21024621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3385 (or 3382 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21024621 is about 4585.2612793602. The cubic root of 21024621 is about 276.0001969123. Note that the first 3 decimals are identical.

Adding to 21024621 its reverse (12642012), we get a palindrome (33666633).

The spelling of 21024621 in words is "twenty-one million, twenty-four thousand, six hundred twenty-one".