20731320 has 48 divisors (see below), whose sum is σ = 67377960.
Its totient is φ = 5528256.
The previous prime is 20731309. The next prime is 20731327. The reversal of 20731320 is 2313702.
It is a Harshad number since it is a multiple of its sum of digits (18).
It is a junction number, because it is equal to n+sod(n) for n = 20731293 and 20731302.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (20731327) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (13) of ones.
It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 28434 + ... + 29153.
Almost surely, 220731320 is an apocalyptic number.
20731320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.
It is an amenable number.
20731320 is an abundant number, since it is smaller than the sum of its proper divisors (46646640).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
20731320 is a wasteful number, since it uses less digits than its factorization.
20731320 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 57604 (or 57597 counting only the distinct ones).
The product of its (nonzero) digits is 252, while the sum is 18.
The square root of 20731320 is about 4553.1659315250.
The cubic root of 20731320 is about 274.7107482061.
The spelling of 20731320 in words is "twenty million, seven hundred thirty-one thousand, three hundred twenty".