21108573 has 8 divisors (see below), whose sum is σ = 31272000. Its totient is φ = 14072364.

The previous prime is 21108557. The next prime is 21108587. The reversal of 21108573 is 37580112.

It is not a de Polignac number, because 21108573 - 2⁴ = 21108557 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 781799 = 21108573 / (2 + 1 + 1 + 0 + 8 + 5 + 7 + 3).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21108553) 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, 390873 + ... + 390926.

It is an arithmetic number, because the mean of its divisors is an integer number (3909000).

Almost surely, 2^21108573 is an apocalyptic number.

It is an amenable number.

21108573 is a deficient number, since it is larger than the sum of its proper divisors (10163427).

21108573 is an equidigital number, since it uses as much as digits as its factorization.

21108573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 781808 (or 781802 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The square root of 21108573 is about 4594.4067081616. The cubic root of 21108573 is about 276.3670683091.

Adding to 21108573 its reverse (37580112), we get a palindrome (58688685).

The spelling of 21108573 in words is "twenty-one million, one hundred eight thousand, five hundred seventy-three".