21168500 has 24 divisors (see below), whose sum is σ = 46233096. Its totient is φ = 8467200.

The previous prime is 21168491. The next prime is 21168509. The reversal of 21168500 is 586112.

It is an interprime number because it is at equal distance from previous prime (21168491) and next prime (21168509).

It can be written as a sum of positive squares in 4 ways, for example, as 26896 + 21141604 = 164^2 + 4598^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21168509) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20669 + ... + 21668.

It is an arithmetic number, because the mean of its divisors is an integer number (1926379).

Almost surely, 2^21168500 is an apocalyptic number.

21168500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21168500 is an abundant number, since it is smaller than the sum of its proper divisors (25064596).

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

21168500 is a wasteful number, since it uses less digits than its factorization.

21168500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42356 (or 42344 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 21168500 is about 4600.9238202778. The cubic root of 21168500 is about 276.6283555280.

The spelling of 21168500 in words is "twenty-one million, one hundred sixty-eight thousand, five hundred".