21512085 has 64 divisors (see below), whose sum is σ = 42577920. Its totient is φ = 9054720.

The previous prime is 21512063. The next prime is 21512093. The reversal of 21512085 is 58021512.

It is not a de Polignac number, because 21512085 - 2⁵ = 21512053 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 81664 + ... + 81926.

It is an arithmetic number, because the mean of its divisors is an integer number (665280).

Almost surely, 2^21512085 is an apocalyptic number.

It is an amenable number.

21512085 is a deficient number, since it is larger than the sum of its proper divisors (21065835).

21512085 is a wasteful number, since it uses less digits than its factorization.

21512085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338.

The product of its (nonzero) digits is 800, while the sum is 24.

The square root of 21512085 is about 4638.1122237393. The cubic root of 21512085 is about 278.1169780121.

Adding to 21512085 its reverse (58021512), we get a palindrome (79533597).

The spelling of 21512085 in words is "twenty-one million, five hundred twelve thousand, eighty-five".