20731245 has 16 divisors (see below), whose sum is σ = 35121600. Its totient is φ = 10406144.

The previous prime is 20731241. The next prime is 20731247. The reversal of 20731245 is 54213702.

It is a cyclic number.

It is not a de Polignac number, because 20731245 - 2² = 20731241 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20731241) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40395 + ... + 40904.

It is an arithmetic number, because the mean of its divisors is an integer number (2195100).

Almost surely, 2^20731245 is an apocalyptic number.

It is an amenable number.

20731245 is a deficient number, since it is larger than the sum of its proper divisors (14390355).

20731245 is a wasteful number, since it uses less digits than its factorization.

20731245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81324.

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 20731245 is about 4553.1576954900. The cubic root of 20731245 is about 274.7104169307.

Adding to 20731245 its reverse (54213702), we get a palindrome (74944947).

It can be divided in two parts, 207312 and 45, that multiplied together give a triangular number (9329040 = T₄₃₁₉).

The spelling of 20731245 in words is "twenty million, seven hundred thirty-one thousand, two hundred forty-five".