20731345 has 8 divisors (see below), whose sum is σ = 24978240.
Its totient is φ = 16518000.
The previous prime is 20731339. The next prime is 20731351. The reversal of 20731345 is 54313702.
It is an interprime number because it is at equal distance from previous prime (20731339) and next prime (20731351).
It is a sphenic number, since it is the product of 3 distinct primes.
It is a de Polignac number, because none of the positive numbers 2k-20731345 is a prime.
It is an unprimeable number.
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 7 ways as a sum of consecutive naturals, for example, 7005 + ... + 9514.
It is an arithmetic number, because the mean of its divisors is an integer number (3122280).
Almost surely, 220731345 is an apocalyptic number.
It is an amenable number.
20731345 is a deficient number, since it is larger than the sum of its proper divisors (4246895).
20731345 is a wasteful number, since it uses less digits than its factorization.
20731345 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 16775.
The product of its (nonzero) digits is 2520, while the sum is 25.
The square root of 20731345 is about 4553.1686768667.
The cubic root of 20731345 is about 274.7108586311.
The spelling of 20731345 in words is "twenty million, seven hundred thirty-one thousand, three hundred forty-five".