21572124 has 48 divisors (see below), whose sum is σ = 58399488. Its totient is φ = 6069888.

The previous prime is 21572119. The next prime is 21572141. The reversal of 21572124 is 42127512.

It is a junction number, because it is equal to n+sod(n) for n = 21572094 and 21572103.

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, 3712 + ... + 7544.

It is an arithmetic number, because the mean of its divisors is an integer number (1216656).

Almost surely, 2^21572124 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 21572124, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29199744).

21572124 is an abundant number, since it is smaller than the sum of its proper divisors (36827364).

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

21572124 is a wasteful number, since it uses less digits than its factorization.

21572124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3914 (or 3912 counting only the distinct ones).

The product of its digits is 1120, while the sum is 24.

The square root of 21572124 is about 4644.5800671320. The cubic root of 21572124 is about 278.3754738765.

Adding to 21572124 its reverse (42127512), we get a palindrome (63699636).

The spelling of 21572124 in words is "twenty-one million, five hundred seventy-two thousand, one hundred twenty-four".