20310985 has 4 divisors (see below), whose sum is σ = 24373188. Its totient is φ = 16248784.

The previous prime is 20310973. The next prime is 20311043. The reversal of 20310985 is 58901302.

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 8311689 + 11999296 = 2883^2 + 3464^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20310985 is a prime.

It is a super-2 number, since 2×20310985² = 825072223340450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2031094 + ... + 2031103.

It is an arithmetic number, because the mean of its divisors is an integer number (6093297).

Almost surely, 2^20310985 is an apocalyptic number.

It is an amenable number.

20310985 is a deficient number, since it is larger than the sum of its proper divisors (4062203).

20310985 is an equidigital number, since it uses as much as digits as its factorization.

20310985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4062202.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 20310985 is about 4506.7710170365. The cubic root of 20310985 is about 272.8414371701.

The spelling of 20310985 in words is "twenty million, three hundred ten thousand, nine hundred eighty-five".