21024856 has 8 divisors (see below), whose sum is σ = 39421620. Its totient is φ = 10512424.

The previous prime is 21024853. The next prime is 21024859. The reversal of 21024856 is 65842012.

It is an interprime number because it is at equal distance from previous prime (21024853) and next prime (21024859).

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

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21024853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1314046 + ... + 1314061.

Almost surely, 2^21024856 is an apocalyptic number.

It is an amenable number.

21024856 is a deficient number, since it is larger than the sum of its proper divisors (18396764).

21024856 is a wasteful number, since it uses less digits than its factorization.

21024856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2628113 (or 2628109 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 21024856 is about 4585.2869048730. The cubic root of 21024856 is about 276.0012252274.

Adding to 21024856 its reverse (65842012), we get a palindrome (86866868).

The spelling of 21024856 in words is "twenty-one million, twenty-four thousand, eight hundred fifty-six".