20011720 has 32 divisors (see below), whose sum is σ = 47676600. Its totient is φ = 7533568.

The previous prime is 20011699. The next prime is 20011723. The reversal of 20011720 is 2711002.

It can be written as a sum of positive squares in 4 ways, for example, as 19945156 + 66564 = 4466^2 + 258^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20011720.

It is not an unprimeable number, because it can be changed into a prime (20011723) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 14035 + ... + 15394.

Almost surely, 2^20011720 is an apocalyptic number.

20011720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20011720 is an abundant number, since it is smaller than the sum of its proper divisors (27664880).

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

20011720 is a wasteful number, since it uses less digits than its factorization.

20011720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29457 (or 29453 counting only the distinct ones).

The product of its (nonzero) digits is 28, while the sum is 13.

The square root of 20011720 is about 4473.4460989264. The cubic root of 20011720 is about 271.4947729301.

Adding to 20011720 its reverse (2711002), we get a palindrome (22722722).

It can be divided in two parts, 2001 and 1720, that added together give a square (3721 = 61²).

The spelling of 20011720 in words is "twenty million, eleven thousand, seven hundred twenty".