20723242 has 4 divisors (see below), whose sum is σ = 31084866. Its totient is φ = 10361620.

The previous prime is 20723239. The next prime is 20723249. The reversal of 20723242 is 24232702.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 14676561 + 6046681 = 3831^2 + 2459^2 .

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (20723249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5180809 + ... + 5180812.

Almost surely, 2^20723242 is an apocalyptic number.

20723242 is a deficient number, since it is larger than the sum of its proper divisors (10361624).

20723242 is a wasteful number, since it uses less digits than its factorization.

20723242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10361623.

The product of its (nonzero) digits is 1344, while the sum is 22.

The square root of 20723242 is about 4552.2787700228. The cubic root of 20723242 is about 274.6750630413.

Adding to 20723242 its reverse (24232702), we get a palindrome (44955944).

The spelling of 20723242 in words is "twenty million, seven hundred twenty-three thousand, two hundred forty-two".