21127656 has 64 divisors (see below), whose sum is σ = 58060800. Its totient is φ = 6353600.

The previous prime is 21127649. The next prime is 21127657. The reversal of 21127656 is 65672112.

Its product of digits (5040) is a multiple of the sum of its prime factors (630).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21127657) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50215 + ... + 50633.

It is an arithmetic number, because the mean of its divisors is an integer number (907200).

Almost surely, 2^21127656 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 21127656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29030400).

21127656 is an abundant number, since it is smaller than the sum of its proper divisors (36933144).

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

21127656 is a wasteful number, since it uses less digits than its factorization.

21127656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630 (or 626 counting only the distinct ones).

The product of its digits is 5040, while the sum is 30.

The square root of 21127656 is about 4596.4830033407. The cubic root of 21127656 is about 276.4503255443.

Adding to 21127656 its reverse (65672112), we get a palindrome (86799768).

The spelling of 21127656 in words is "twenty-one million, one hundred twenty-seven thousand, six hundred fifty-six".