21024955 has 16 divisors (see below), whose sum is σ = 28914624. Its totient is φ = 14376960.

The previous prime is 21024953. The next prime is 21024959. The reversal of 21024955 is 55942012.

It is not a de Polignac number, because 21024955 - 2¹ = 21024953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21024953) 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 15 ways as a sum of consecutive naturals, for example, 17659 + ... + 18811.

It is an arithmetic number, because the mean of its divisors is an integer number (1807164).

Almost surely, 2^21024955 is an apocalyptic number.

21024955 is a deficient number, since it is larger than the sum of its proper divisors (7889669).

21024955 is a wasteful number, since it uses less digits than its factorization.

21024955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1686.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 21024955 is about 4585.2977002589. The cubic root of 21024955 is about 276.0016584301.

Adding to 21024955 its reverse (55942012), we get a palindrome (76966967).

It can be divided in two parts, 2102495 and 5, that added together give a square (2102500 = 1450²).

The spelling of 21024955 in words is "twenty-one million, twenty-four thousand, nine hundred fifty-five".