20985079 has 4 divisors (see below), whose sum is σ = 21004984. Its totient is φ = 20965176.

The previous prime is 20985059. The next prime is 20985113. The reversal of 20985079 is 97058902.

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

It is a cyclic number.

It is not a de Polignac number, because 20985079 - 2¹¹ = 20983031 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 (20985049) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8277 + ... + 10510.

It is an arithmetic number, because the mean of its divisors is an integer number (5251246).

Almost surely, 2^20985079 is an apocalyptic number.

20985079 is a deficient number, since it is larger than the sum of its proper divisors (19905).

20985079 is a wasteful number, since it uses less digits than its factorization.

20985079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19904.

The product of its (nonzero) digits is 45360, while the sum is 40.

The square root of 20985079 is about 4580.9473910972. The cubic root of 20985079 is about 275.8270594456.

The spelling of 20985079 in words is "twenty million, nine hundred eighty-five thousand, seventy-nine".