20724242 has 32 divisors (see below), whose sum is σ = 40449024. Its totient is φ = 7722000.

The previous prime is 20724233. The next prime is 20724251. The reversal of 20724242 is 24242702.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20724233) and next prime (20724251).

It is a Harshad number since it is a multiple of its sum of digits (23).

20724242 is a modest number, since divided by 4242 gives 2072 as remainder.

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 15 ways as a sum of consecutive naturals, for example, 617 + ... + 6467.

It is an arithmetic number, because the mean of its divisors is an integer number (1264032).

Almost surely, 2^20724242 is an apocalyptic number.

20724242 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

20724242 is a deficient number, since it is larger than the sum of its proper divisors (19724782).

20724242 is a wasteful number, since it uses less digits than its factorization.

20724242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5894.

The product of its (nonzero) digits is 1792, while the sum is 23.

The square root of 20724242 is about 4552.3886037991. The cubic root of 20724242 is about 274.6794811184.

Adding to 20724242 its reverse (24242702), we get a palindrome (44966944).

The spelling of 20724242 in words is "twenty million, seven hundred twenty-four thousand, two hundred forty-two".