21980085 has 16 divisors (see below), whose sum is σ = 36303360. Its totient is φ = 11344320.

The previous prime is 21980053. The next prime is 21980117. The reversal of 21980085 is 58008912.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21980053) and next prime (21980117).

It is not a de Polignac number, because 21980085 - 2⁵ = 21980053 is a prime.

It is a Curzon number.

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, 23170 + ... + 24099.

It is an arithmetic number, because the mean of its divisors is an integer number (2268960).

Almost surely, 2^21980085 is an apocalyptic number.

It is an amenable number.

21980085 is a deficient number, since it is larger than the sum of its proper divisors (14323275).

21980085 is a wasteful number, since it uses less digits than its factorization.

21980085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47308.

The product of its (nonzero) digits is 5760, while the sum is 33.

The square root of 21980085 is about 4688.2923330356. The cubic root of 21980085 is about 280.1193581265.

Adding to 21980085 its reverse (58008912), we get a palindrome (79988997).

The spelling of 21980085 in words is "twenty-one million, nine hundred eighty thousand, eighty-five".