5405821 has 2 divisors, whose sum is σ = 5405822. Its totient is φ = 5405820.

The previous prime is 5405819. The next prime is 5405837. The reversal of 5405821 is 1285045.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5405625 + 196 = 2325^2 + 14^2 .

It is a cyclic number.

It is not a de Polignac number, because 5405821 - 2¹ = 5405819 is a prime.

Together with 5405819, it forms a pair of twin primes.

It is an Ulam number.

5405821 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5405021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2702910 + 2702911.

It is an arithmetic number, because the mean of its divisors is an integer number (2702911).

Almost surely, 2^5405821 is an apocalyptic number.

It is an amenable number.

5405821 is a deficient number, since it is larger than the sum of its proper divisors (1).

5405821 is an equidigital number, since it uses as much as digits as its factorization.

5405821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1600, while the sum is 25.

The square root of 5405821 is about 2325.0421501556. The cubic root of 5405821 is about 175.5040813114.

It can be divided in two parts, 5405 and 821, that added together give a palindrome (6226).

The spelling of 5405821 in words is "five million, four hundred five thousand, eight hundred twenty-one".