20038721 has 4 divisors (see below), whose sum is σ = 20050944. Its totient is φ = 20026500.

The previous prime is 20038687. The next prime is 20038723. The reversal of 20038721 is 12783002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12783002 = 2 ⋅6391501.

It is a cyclic number.

It is not a de Polignac number, because 20038721 - 2²² = 15844417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20038723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3185 + ... + 7086.

It is an arithmetic number, because the mean of its divisors is an integer number (5012736).

Almost surely, 2^20038721 is an apocalyptic number.

It is an amenable number.

20038721 is a deficient number, since it is larger than the sum of its proper divisors (12223).

20038721 is a wasteful number, since it uses less digits than its factorization.

20038721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12222.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 20038721 is about 4476.4630010757. The cubic root of 20038721 is about 271.6168236727.

The spelling of 20038721 in words is "twenty million, thirty-eight thousand, seven hundred twenty-one".