20731145 has 8 divisors (see below), whose sum is σ = 24929856. Its totient is φ = 16549936.

The previous prime is 20731133. The next prime is 20731153. The reversal of 20731145 is 54113702.

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

It is a cyclic number.

It is not a de Polignac number, because 20731145 - 2⁴ = 20731129 is a prime.

It is a super-2 number, since 2×20731145² = 859560746022050, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20731145.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1607 + ... + 6636.

It is an arithmetic number, because the mean of its divisors is an integer number (3116232).

Almost surely, 2^20731145 is an apocalyptic number.

It is an amenable number.

20731145 is a deficient number, since it is larger than the sum of its proper divisors (4198711).

20731145 is an equidigital number, since it uses as much as digits as its factorization.

20731145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8751.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 20731145 is about 4553.1467140869. The cubic root of 20731145 is about 274.7099752288.

Adding to 20731145 its reverse (54113702), we get a palindrome (74844847).

The spelling of 20731145 in words is "twenty million, seven hundred thirty-one thousand, one hundred forty-five".