521220345 has 8 divisors (see below), whose sum is σ = 833952576. Its totient is φ = 277984176.

The previous prime is 521220341. The next prime is 521220347. The reversal of 521220345 is 543022125.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 521220345 - 2² = 521220341 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (521220341) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17373997 + ... + 17374026.

It is an arithmetic number, because the mean of its divisors is an integer number (104244072).

Almost surely, 2^521220345 is an apocalyptic number.

It is an amenable number.

521220345 is a deficient number, since it is larger than the sum of its proper divisors (312732231).

521220345 is a wasteful number, since it uses less digits than its factorization.

521220345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34748031.

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 521220345 is about 22830.2506556542. The cubic root of 521220345 is about 804.7737208483.

The spelling of 521220345 in words is "five hundred twenty-one million, two hundred twenty thousand, three hundred forty-five".