21121300 has 18 divisors (see below), whose sum is σ = 45833438. Its totient is φ = 8448480.

The previous prime is 21121277. The next prime is 21121319. The reversal of 21121300 is 312112.

It can be written as a sum of positive squares in 3 ways, for example, as 163216 + 20958084 = 404^2 + 4578^2 .

It is a super-2 number, since 2×21121300² = 892218627380000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 105507 + ... + 105706.

Almost surely, 2^21121300 is an apocalyptic number.

21121300 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121300 is an abundant number, since it is smaller than the sum of its proper divisors (24712138).

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

21121300 is a wasteful number, since it uses less digits than its factorization.

21121300 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211227 (or 211220 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 21121300 is about 4595.7915531495. The cubic root of 21121300 is about 276.4226005173.

Adding to 21121300 its reverse (312112), we get a palindrome (21433412).

The spelling of 21121300 in words is "twenty-one million, one hundred twenty-one thousand, three hundred".