21018085 has 16 divisors (see below), whose sum is σ = 28964160. Its totient is φ = 14480640.

The previous prime is 21018079. The next prime is 21018091. The reversal of 21018085 is 58081012.

It is an interprime number because it is at equal distance from previous prime (21018079) and next prime (21018091).

It is not a de Polignac number, because 21018085 - 2⁹ = 21017573 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9012 + ... + 11101.

It is an arithmetic number, because the mean of its divisors is an integer number (1810260).

Almost surely, 2^21018085 is an apocalyptic number.

It is an amenable number.

21018085 is a deficient number, since it is larger than the sum of its proper divisors (7946075).

21018085 is a wasteful number, since it uses less digits than its factorization.

21018085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20148.

The product of its (nonzero) digits is 640, while the sum is 25.

The square root of 21018085 is about 4584.5485055783. The cubic root of 21018085 is about 275.9715935548.

Adding to 21018085 its reverse (58081012), we get a palindrome (79099097).

The spelling of 21018085 in words is "twenty-one million, eighteen thousand, eighty-five".