20636720 has 40 divisors (see below), whose sum is σ = 51673776. Its totient is φ = 7619328.

The previous prime is 20636701. The next prime is 20636723. The reversal of 20636720 is 2763602.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a self number, because there is not a number n which added to its sum of digits gives 20636720.

It is not an unprimeable number, because it can be changed into a prime (20636723) 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, 8882 + ... + 10961.

Almost surely, 2^20636720 is an apocalyptic number.

20636720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20636720 is an abundant number, since it is smaller than the sum of its proper divisors (31037056).

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

20636720 is a wasteful number, since it uses less digits than its factorization.

20636720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19869 (or 19863 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 26.

The square root of 20636720 is about 4542.7656774260. The cubic root of 20636720 is about 274.2922627818.

The spelling of 20636720 in words is "twenty million, six hundred thirty-six thousand, seven hundred twenty".