21085953 has 32 divisors (see below), whose sum is σ = 34636800. Its totient is φ = 11140416.

The previous prime is 21085943. The next prime is 21085979. The reversal of 21085953 is 35958012.

It is not a de Polignac number, because 21085953 - 2¹² = 21081857 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21085943) 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 31 ways as a sum of consecutive naturals, for example, 16543 + ... + 17771.

It is an arithmetic number, because the mean of its divisors is an integer number (1082400).

Almost surely, 2^21085953 is an apocalyptic number.

It is an amenable number.

21085953 is a deficient number, since it is larger than the sum of its proper divisors (13550847).

21085953 is a wasteful number, since it uses less digits than its factorization.

21085953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1301.

The product of its (nonzero) digits is 10800, while the sum is 33.

The square root of 21085953 is about 4591.9443594190. The cubic root of 21085953 is about 276.2683144768.

The spelling of 21085953 in words is "twenty-one million, eighty-five thousand, nine hundred fifty-three".