20685831 has 8 divisors (see below), whose sum is σ = 27684720. Its totient is φ = 13738752.

The previous prime is 20685823. The next prime is 20685869. The reversal of 20685831 is 13858602.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20685831 - 2³ = 20685823 is a prime.

It is a super-2 number, since 2×20685831² = 855807208321122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20685792 and 20685801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20685811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12010 + ... + 13623.

It is an arithmetic number, because the mean of its divisors is an integer number (3460590).

Almost surely, 2^20685831 is an apocalyptic number.

20685831 is a deficient number, since it is larger than the sum of its proper divisors (6998889).

20685831 is a wasteful number, since it uses less digits than its factorization.

20685831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25905.

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 20685831 is about 4548.1678728912. The cubic root of 20685831 is about 274.5096761364.

The spelling of 20685831 in words is "twenty million, six hundred eighty-five thousand, eight hundred thirty-one".