21127500 has 120 divisors (see below), whose sum is σ = 68665520. Its totient is φ = 5616000.

The previous prime is 21127499. The next prime is 21127507. The reversal of 21127500 is 572112.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21127507) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 67344 + ... + 67656.

Almost surely, 2^21127500 is an apocalyptic number.

21127500 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 21127500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34332760).

21127500 is an abundant number, since it is smaller than the sum of its proper divisors (47538020).

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

21127500 is a wasteful number, since it uses less digits than its factorization.

21127500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 346 (or 323 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 21127500 is about 4596.4660338134. The cubic root of 21127500 is about 276.4496451351.

Adding to 21127500 its reverse (572112), we get a palindrome (21699612).

The spelling of 21127500 in words is "twenty-one million, one hundred twenty-seven thousand, five hundred".