21810124 has 12 divisors (see below), whose sum is σ = 43620304. Its totient is φ = 9347184.

The previous prime is 21810121. The next prime is 21810127. The reversal of 21810124 is 42101812.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21810121) and next prime (21810127).

21810124 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (21810121) 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 3 ways as a sum of consecutive naturals, for example, 389439 + ... + 389494.

Almost surely, 2^21810124 is an apocalyptic number.

It is an amenable number.

21810124 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21810124 is a wasteful number, since it uses less digits than its factorization.

21810124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 778944 (or 778942 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 21810124 is about 4670.1310474118. The cubic root of 21810124 is about 279.3954815014.

Adding to 21810124 its reverse (42101812), we get a palindrome (63911936).

The spelling of 21810124 in words is "twenty-one million, eight hundred ten thousand, one hundred twenty-four".