21047124 has 48 divisors (see below), whose sum is σ = 57440768. Its totient is φ = 5872608.

The previous prime is 21047119. The next prime is 21047149. The reversal of 21047124 is 42174012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 21047124.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 699 + ... + 6525.

Almost surely, 2^21047124 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21047124, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28720384).

21047124 is an abundant number, since it is smaller than the sum of its proper divisors (36393644).

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

21047124 is a wasteful number, since it uses less digits than its factorization.

21047124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5884 (or 5882 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 21.

The square root of 21047124 is about 4587.7144636518. The cubic root of 21047124 is about 276.0986309957.

The spelling of 21047124 in words is "twenty-one million, forty-seven thousand, one hundred twenty-four".