20724263 has 4 divisors (see below), whose sum is σ = 23684880. Its totient is φ = 17763648.

The previous prime is 20724259. The next prime is 20724287. The reversal of 20724263 is 36242702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 36242702 = 2 ⋅18121351.

It is not a de Polignac number, because 20724263 - 2² = 20724259 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20724233) 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 3 ways as a sum of consecutive naturals, for example, 1480298 + ... + 1480311.

It is an arithmetic number, because the mean of its divisors is an integer number (5921220).

Almost surely, 2^20724263 is an apocalyptic number.

20724263 is a deficient number, since it is larger than the sum of its proper divisors (2960617).

20724263 is an equidigital number, since it uses as much as digits as its factorization.

20724263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2960616.

The product of its (nonzero) digits is 4032, while the sum is 26.

The square root of 20724263 is about 4552.3909102800. The cubic root of 20724263 is about 274.6795738965.

Adding to 20724263 its reverse (36242702), we get a palindrome (56966965).

The spelling of 20724263 in words is "twenty million, seven hundred twenty-four thousand, two hundred sixty-three".