21127660 has 48 divisors (see below), whose sum is σ = 46620000. Its totient is φ = 8031744.

The previous prime is 21127657. The next prime is 21127661. The reversal of 21127660 is 6672112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21127661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42091 + ... + 42589.

It is an arithmetic number, because the mean of its divisors is an integer number (971250).

Almost surely, 2^21127660 is an apocalyptic number.

21127660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21127660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23310000).

21127660 is an abundant number, since it is smaller than the sum of its proper divisors (25492340).

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

21127660 is a wasteful number, since it uses less digits than its factorization.

21127660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610 (or 608 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 21127660 is about 4596.4834384560. The cubic root of 21127660 is about 276.4503429907.

Adding to 21127660 its reverse (6672112), we get a palindrome (27799772).

The spelling of 21127660 in words is "twenty-one million, one hundred twenty-seven thousand, six hundred sixty".