21090895 has 8 divisors (see below), whose sum is σ = 28924704. Its totient is φ = 14462304.

The previous prime is 21090889. The next prime is 21090899. The reversal of 21090895 is 59809012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21090895 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21090895.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21090899) 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, 301264 + ... + 301333.

It is an arithmetic number, because the mean of its divisors is an integer number (3615588).

Almost surely, 2^21090895 is an apocalyptic number.

21090895 is a deficient number, since it is larger than the sum of its proper divisors (7833809).

21090895 is an equidigital number, since it uses as much as digits as its factorization.

21090895 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 602609.

The product of its (nonzero) digits is 6480, while the sum is 34.

The square root of 21090895 is about 4592.4824441689. The cubic root of 21090895 is about 276.2898961646.

The spelling of 21090895 in words is "twenty-one million, ninety thousand, eight hundred ninety-five".