521440823 has 4 divisors (see below), whose sum is σ = 521490288. Its totient is φ = 521391360.

The previous prime is 521440817. The next prime is 521440859. The reversal of 521440823 is 328044125.

It is a happy number.

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 is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-521440823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521443823) 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, 1883 + ... + 32348.

It is an arithmetic number, because the mean of its divisors is an integer number (130372572).

Almost surely, 2^521440823 is an apocalyptic number.

521440823 is a deficient number, since it is larger than the sum of its proper divisors (49465).

521440823 is a wasteful number, since it uses less digits than its factorization.

521440823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49464.

The product of its (nonzero) digits is 7680, while the sum is 29.

The square root of 521440823 is about 22835.0787824347. The cubic root of 521440823 is about 804.8871788701.

Adding to 521440823 its reverse (328044125), we get a palindrome (849484948).

The spelling of 521440823 in words is "five hundred twenty-one million, four hundred forty thousand, eight hundred twenty-three".