21242830 has 16 divisors (see below), whose sum is σ = 43699680. Its totient is φ = 7283232.

The previous prime is 21242827. The next prime is 21242833. The reversal of 21242830 is 3824212.

It is an interprime number because it is at equal distance from previous prime (21242827) and next prime (21242833).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242833) 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 7 ways as a sum of consecutive naturals, for example, 151665 + ... + 151804.

It is an arithmetic number, because the mean of its divisors is an integer number (2731230).

Almost surely, 2^21242830 is an apocalyptic number.

21242830 is an abundant number, since it is smaller than the sum of its proper divisors (22456850).

21242830 is a wasteful number, since it uses less digits than its factorization.

21242830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303483.

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 21242830 is about 4608.9944673432. The cubic root of 21242830 is about 276.9517569022.

The spelling of 21242830 in words is "twenty-one million, two hundred forty-two thousand, eight hundred thirty".