21727926 has 80 divisors (see below), whose sum is σ = 54101520. Its totient is φ = 6462720.

The previous prime is 21727913. The next prime is 21727961. The reversal of 21727926 is 62972712.

It is a super-2 number, since 2×21727926² = 944205536522952, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 158530 + ... + 158666.

It is an arithmetic number, because the mean of its divisors is an integer number (676269).

Almost surely, 2^21727926 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21727926, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27050760).

21727926 is an abundant number, since it is smaller than the sum of its proper divisors (32373594).

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

21727926 is a wasteful number, since it uses less digits than its factorization.

21727926 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251 (or 242 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The square root of 21727926 is about 4661.3223445713. The cubic root of 21727926 is about 279.0440443820.

The spelling of 21727926 in words is "twenty-one million, seven hundred twenty-seven thousand, nine hundred twenty-six".