20434921 has 8 divisors (see below), whose sum is σ = 22717184. Its totient is φ = 18254160.

The previous prime is 20434913. The next prime is 20434951. The reversal of 20434921 is 12943402.

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

It is a cyclic number.

It is not a de Polignac number, because 20434921 - 2³ = 20434913 is a prime.

It is the 4521-st Hogben number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20434951) by changing a digit.

It is a nontrivial repunit in base 4520.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24951 + ... + 25756.

It is an arithmetic number, because the mean of its divisors is an integer number (2839648).

Almost surely, 2^20434921 is an apocalyptic number.

It is an amenable number.

20434921 is a deficient number, since it is larger than the sum of its proper divisors (2282263).

20434921 is a wasteful number, since it uses less digits than its factorization.

20434921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50751.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 20434921 is about 4520.5000829554. The cubic root of 20434921 is about 273.3952644055.

The spelling of 20434921 in words is "twenty million, four hundred thirty-four thousand, nine hundred twenty-one".