20724270 has 128 divisors (see below), whose sum is σ = 60963840. Its totient is φ = 4408320.

The previous prime is 20724259. The next prime is 20724287. The reversal of 20724270 is 7242702.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20724270.

It is a congruent number.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 249649 + ... + 249731.

It is an arithmetic number, because the mean of its divisors is an integer number (476280).

Almost surely, 2^20724270 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20724270, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30481920).

20724270 is an abundant number, since it is smaller than the sum of its proper divisors (40239570).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20724270 is a wasteful number, since it uses less digits than its factorization.

20724270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170.

The product of its (nonzero) digits is 1568, while the sum is 24.

The square root of 20724270 is about 4552.3916791067. The cubic root of 20724270 is about 274.6796048225.

Subtracting from 20724270 its product of nonzero digits (1568), we obtain a palindrome (20722702).

Adding to 20724270 its reverse (7242702), we get a palindrome (27966972).

The spelling of 20724270 in words is "twenty million, seven hundred twenty-four thousand, two hundred seventy".