21958085 has 4 divisors (see below), whose sum is σ = 26349708. Its totient is φ = 17566464.

The previous prime is 21958081. The next prime is 21958093. The reversal of 21958085 is 58085912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5692996 + 16265089 = 2386^2 + 4033^2 .

It is a cyclic number.

It is not a de Polignac number, because 21958085 - 2² = 21958081 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21958081) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 2195804 + ... + 2195813.

It is an arithmetic number, because the mean of its divisors is an integer number (6587427).

Almost surely, 2^21958085 is an apocalyptic number.

It is an amenable number.

21958085 is a deficient number, since it is larger than the sum of its proper divisors (4391623).

21958085 is an equidigital number, since it uses as much as digits as its factorization.

21958085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4391622.

The product of its (nonzero) digits is 28800, while the sum is 38.

The square root of 21958085 is about 4685.9454755684. The cubic root of 21958085 is about 280.0258692085.

The spelling of 21958085 in words is "twenty-one million, nine hundred fifty-eight thousand, eighty-five".