21124278 has 48 divisors (see below), whose sum is σ = 52565760. Its totient is φ = 6005808.

The previous prime is 21124277. The next prime is 21124289. The reversal of 21124278 is 87242112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21124273) 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 23 ways as a sum of consecutive naturals, for example, 45001 + ... + 45467.

It is an arithmetic number, because the mean of its divisors is an integer number (1095120).

Almost surely, 2^21124278 is an apocalyptic number.

21124278 is an abundant number, since it is smaller than the sum of its proper divisors (31441482).

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

21124278 is a wasteful number, since it uses less digits than its factorization.

21124278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 841 (or 838 counting only the distinct ones).

The product of its digits is 1792, while the sum is 27.

The square root of 21124278 is about 4596.1155337959. The cubic root of 21124278 is about 276.4355913183.

The spelling of 21124278 in words is "twenty-one million, one hundred twenty-four thousand, two hundred seventy-eight".