20012721 has 8 divisors (see below), whose sum is σ = 26706144. Its totient is φ = 13330560.

The previous prime is 20012687. The next prime is 20012743. The reversal of 20012721 is 12721002.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20012721 - 2⁷ = 20012593 is a prime.

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 20012721.

It is not an unprimeable number, because it can be changed into a prime (20012761) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 3126 + ... + 7056.

It is an arithmetic number, because the mean of its divisors is an integer number (3338268).

Almost surely, 2^20012721 is an apocalyptic number.

It is an amenable number.

20012721 is a deficient number, since it is larger than the sum of its proper divisors (6693423).

20012721 is a wasteful number, since it uses less digits than its factorization.

20012721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5631.

The product of its (nonzero) digits is 56, while the sum is 15.

The square root of 20012721 is about 4473.5579799529. The cubic root of 20012721 is about 271.4992996397.

Adding to 20012721 its reverse (12721002), we get a palindrome (32733723).

It can be divided in two parts, 200 and 12721, that added together give a palindrome (12921).

The spelling of 20012721 in words is "twenty million, twelve thousand, seven hundred twenty-one".