21342985 has 32 divisors (see below), whose sum is σ = 28569600. Its totient is φ = 15240960.

The previous prime is 21342967. The next prime is 21342989. The reversal of 21342985 is 58924312.

It is not a de Polignac number, because 21342985 - 2⁵ = 21342953 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21342985.

It is not an unprimeable number, because it can be changed into a prime (21342989) 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, 167992 + ... + 168118.

It is an arithmetic number, because the mean of its divisors is an integer number (892800).

Almost surely, 2^21342985 is an apocalyptic number.

It is an amenable number.

21342985 is a deficient number, since it is larger than the sum of its proper divisors (7226615).

21342985 is a wasteful number, since it uses less digits than its factorization.

21342985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241.

The product of its digits is 17280, while the sum is 34.

The square root of 21342985 is about 4619.8468589337. The cubic root of 21342985 is about 277.3863290086.

The spelling of 21342985 in words is "twenty-one million, three hundred forty-two thousand, nine hundred eighty-five".