20734021 has 16 divisors (see below), whose sum is σ = 26242560. Its totient is φ = 15911280.

The previous prime is 20734013. The next prime is 20734027. The reversal of 20734021 is 12043702.

It is not a de Polignac number, because 20734021 - 2³ = 20734013 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20734021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20734027) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3150 + ... + 7168.

It is an arithmetic number, because the mean of its divisors is an integer number (1640160).

Almost surely, 2^20734021 is an apocalyptic number.

It is an amenable number.

20734021 is a deficient number, since it is larger than the sum of its proper divisors (5508539).

20734021 is a wasteful number, since it uses less digits than its factorization.

20734021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4104.

The product of its (nonzero) digits is 336, while the sum is 19.

The square root of 20734021 is about 4553.4625286698. The cubic root of 20734021 is about 274.7226780062.

Adding to 20734021 its reverse (12043702), we get a palindrome (32777723).

The spelling of 20734021 in words is "twenty million, seven hundred thirty-four thousand, twenty-one".