21024999 has 6 divisors (see below), whose sum is σ = 30369456. Its totient is φ = 14016660.

The previous prime is 21024961. The next prime is 21025019. The reversal of 21024999 is 99942012.

It is not a de Polignac number, because 21024999 - 2⁸ = 21024743 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21024959) 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 5 ways as a sum of consecutive naturals, for example, 1168047 + ... + 1168064.

It is an arithmetic number, because the mean of its divisors is an integer number (5061576).

Almost surely, 2^21024999 is an apocalyptic number.

21024999 is a deficient number, since it is larger than the sum of its proper divisors (9344457).

21024999 is a wasteful number, since it uses less digits than its factorization.

21024999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2336117 (or 2336114 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 21024999 is about 4585.3024982001. The cubic root of 21024999 is about 276.0018509643.

The spelling of 21024999 in words is "twenty-one million, twenty-four thousand, nine hundred ninety-nine".