2005521421 has 6 divisors (see below), whose sum is σ = 2116631022. Its totient is φ = 1899967320.

The previous prime is 2005521407. The next prime is 2005521439. The reversal of 2005521421 is 1241255002.

It can be written as a sum of positive squares in only one way, i.e., 1458476100 + 547045321 = 38190^2 + 23389^2 .

It is not a de Polignac number, because 2005521421 - 2¹⁷ = 2005390349 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2005521392 and 2005521401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2005521121) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2777370 + ... + 2778091.

It is an arithmetic number, because the mean of its divisors is an integer number (352771837).

Almost surely, 2^2005521421 is an apocalyptic number.

It is an amenable number.

2005521421 is a deficient number, since it is larger than the sum of its proper divisors (111109601).

2005521421 is an equidigital number, since it uses as much as digits as its factorization.

2005521421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5555499 (or 5555480 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 22.

The square root of 2005521421 is about 44783.0483665416. The cubic root of 2005521421 is about 1261.0794103392.

Adding to 2005521421 its reverse (1241255002), we get a palindrome (3246776423).

The spelling of 2005521421 in words is "two billion, five million, five hundred twenty-one thousand, four hundred twenty-one".