20708681 has 4 divisors (see below), whose sum is σ = 23667072. Its totient is φ = 17750292.

The previous prime is 20708663. The next prime is 20708693. The reversal of 20708681 is 18680702.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20708681 - 2¹⁴ = 20692297 is a prime.

It is a super-2 number, since 2×20708681² = 857698937519522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20708381) 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, 1479185 + ... + 1479198.

It is an arithmetic number, because the mean of its divisors is an integer number (5916768).

Almost surely, 2^20708681 is an apocalyptic number.

It is an amenable number.

20708681 is a deficient number, since it is larger than the sum of its proper divisors (2958391).

20708681 is an equidigital number, since it uses as much as digits as its factorization.

20708681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2958390.

The product of its (nonzero) digits is 5376, while the sum is 32.

The square root of 20708681 is about 4550.6791800785. The cubic root of 20708681 is about 274.6107153118.

The spelling of 20708681 in words is "twenty million, seven hundred eight thousand, six hundred eighty-one".