20055421 has 4 divisors (see below), whose sum is σ = 20065500. Its totient is φ = 20045344.

The previous prime is 20055407. The next prime is 20055433. The reversal of 20055421 is 12455002.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 17131321 + 2924100 = 4139^2 + 1710^2 .

It is a cyclic number.

It is not a de Polignac number, because 20055421 - 2¹⁷ = 19924349 is a prime.

It is a super-2 number, since 2×20055421² = 804439822974482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20055491) 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, 946 + ... + 6403.

It is an arithmetic number, because the mean of its divisors is an integer number (5016375).

Almost surely, 2^20055421 is an apocalyptic number.

It is an amenable number.

20055421 is a deficient number, since it is larger than the sum of its proper divisors (10079).

20055421 is an equidigital number, since it uses as much as digits as its factorization.

20055421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10078.

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 20055421 is about 4478.3279245718. The cubic root of 20055421 is about 271.6922566549.

The spelling of 20055421 in words is "twenty million, fifty-five thousand, four hundred twenty-one".