21088807 has 4 divisors (see below), whose sum is σ = 21098880. Its totient is φ = 21078736.

The previous prime is 21088799. The next prime is 21088819. The reversal of 21088807 is 70888012.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21088807 - 2³ = 21088799 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21088607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 583 + ... + 6520.

It is an arithmetic number, because the mean of its divisors is an integer number (5274720).

Almost surely, 2^21088807 is an apocalyptic number.

21088807 is a deficient number, since it is larger than the sum of its proper divisors (10073).

21088807 is an equidigital number, since it uses as much as digits as its factorization.

21088807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10072.

The product of its (nonzero) digits is 7168, while the sum is 34.

The square root of 21088807 is about 4592.2551105094. The cubic root of 21088807 is about 276.2807782910.

The spelling of 21088807 in words is "twenty-one million, eighty-eight thousand, eight hundred seven".