20071720 has 32 divisors (see below), whose sum is σ = 45325800. Its totient is φ = 7999488.

The previous prime is 20071699. The next prime is 20071721. The reversal of 20071720 is 2717002.

It can be written as a sum of positive squares in 4 ways, for example, as 11035684 + 9036036 = 3322^2 + 3006^2 .

It is not an unprimeable number, because it can be changed into a prime (20071721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12736 + ... + 14224.

Almost surely, 2^20071720 is an apocalyptic number.

20071720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20071720 is an abundant number, since it is smaller than the sum of its proper divisors (25254080).

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

20071720 is a wasteful number, since it uses less digits than its factorization.

20071720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1837 (or 1833 counting only the distinct ones).

The product of its (nonzero) digits is 196, while the sum is 19.

The square root of 20071720 is about 4480.1473190064. The cubic root of 20071720 is about 271.7658379742.

Adding to 20071720 its reverse (2717002), we get a palindrome (22788722).

The spelling of 20071720 in words is "twenty million, seventy-one thousand, seven hundred twenty".