21168845 has 4 divisors (see below), whose sum is σ = 25402620. Its totient is φ = 16935072.

The previous prime is 21168827. The next prime is 21168871. The reversal of 21168845 is 54886112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6522916 + 14645929 = 2554^2 + 3827^2 .

It is a cyclic number.

It is not a de Polignac number, because 21168845 - 2¹⁶ = 21103309 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2116880 + ... + 2116889.

It is an arithmetic number, because the mean of its divisors is an integer number (6350655).

Almost surely, 2^21168845 is an apocalyptic number.

It is an amenable number.

21168845 is a deficient number, since it is larger than the sum of its proper divisors (4233775).

21168845 is an equidigital number, since it uses as much as digits as its factorization.

21168845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4233774.

The product of its digits is 15360, while the sum is 35.

The square root of 21168845 is about 4600.9613125954. The cubic root of 21168845 is about 276.6298583312.

The spelling of 21168845 in words is "twenty-one million, one hundred sixty-eight thousand, eight hundred forty-five".