20621873 has 4 divisors (see below), whose sum is σ = 20735988. Its totient is φ = 20507760.

The previous prime is 20621827. The next prime is 20621891. The reversal of 20621873 is 37812602.

It is a happy number.

20621873 is nontrivially palindromic in base 16.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 37812602 = 2 ⋅18906301.

It can be written as a sum of positive squares in 2 ways, for example, as 5513104 + 15108769 = 2348^2 + 3887^2 .

It is a cyclic number.

It is not a de Polignac number, because 20621873 - 2¹⁰ = 20620849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20621273) 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, 56786 + ... + 57147.

It is an arithmetic number, because the mean of its divisors is an integer number (5183997).

Almost surely, 2^20621873 is an apocalyptic number.

It is an amenable number.

20621873 is a deficient number, since it is larger than the sum of its proper divisors (114115).

20621873 is a wasteful number, since it uses less digits than its factorization.

20621873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114114.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 20621873 is about 4541.1312467270. The cubic root of 20621873 is about 274.2264675352.

The spelling of 20621873 in words is "twenty million, six hundred twenty-one thousand, eight hundred seventy-three".