521220001 has 4 divisors (see below), whose sum is σ = 528999472. Its totient is φ = 513440532.

The previous prime is 521219953. The next prime is 521220013. The reversal of 521220001 is 100022125.

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.

It is a cyclic number.

It is not a de Polignac number, because 521220001 - 2⁷ = 521219873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (521220031) 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, 3889635 + ... + 3889768.

It is an arithmetic number, because the mean of its divisors is an integer number (132249868).

Almost surely, 2^521220001 is an apocalyptic number.

It is an amenable number.

521220001 is a deficient number, since it is larger than the sum of its proper divisors (7779471).

521220001 is an equidigital number, since it uses as much as digits as its factorization.

521220001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7779470.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 521220001 is about 22830.2431217891. The cubic root of 521220001 is about 804.7735438008.

Adding to 521220001 its reverse (100022125), we get a palindrome (621242126).

The spelling of 521220001 in words is "five hundred twenty-one million, two hundred twenty thousand, one".