21124390 has 48 divisors (see below), whose sum is σ = 46580400. Its totient is φ = 6858432.

The previous prime is 21124357. The next prime is 21124391. The reversal of 21124390 is 9342112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21124391) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8176 + ... + 10444.

It is an arithmetic number, because the mean of its divisors is an integer number (970425).

Almost surely, 2^21124390 is an apocalyptic number.

21124390 is an abundant number, since it is smaller than the sum of its proper divisors (25456010).

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

21124390 is a wasteful number, since it uses less digits than its factorization.

21124390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2309 (or 2302 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 21124390 is about 4596.1277179817. The cubic root of 21124390 is about 276.4360798673.

The spelling of 21124390 in words is "twenty-one million, one hundred twenty-four thousand, three hundred ninety".