505021421 has 4 divisors (see below), whose sum is σ = 505189152. Its totient is φ = 504853692.

The previous prime is 505021357. The next prime is 505021453. The reversal of 505021421 is 124120505.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 124120505 = 5 ⋅24824101.

It is a cyclic number.

It is not a de Polignac number, because 505021421 - 2⁶ = 505021357 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 505021393 and 505021402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (505020421) 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, 79265 + ... + 85398.

It is an arithmetic number, because the mean of its divisors is an integer number (126297288).

Almost surely, 2^505021421 is an apocalyptic number.

It is an amenable number.

505021421 is a deficient number, since it is larger than the sum of its proper divisors (167731).

505021421 is a wasteful number, since it uses less digits than its factorization.

505021421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167730.

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 505021421 is about 22472.6816601847. The cubic root of 505021421 is about 796.3486836527.

Adding to 505021421 its reverse (124120505), we get a palindrome (629141926).

The spelling of 505021421 in words is "five hundred five million, twenty-one thousand, four hundred twenty-one".