221450601521 has 4 divisors (see below), whose sum is σ = 228594169344. Its totient is φ = 214307033700.

The previous prime is 221450601511. The next prime is 221450601539. The reversal of 221450601521 is 125106054122.

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 221450601521 - 2⁶ = 221450601457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221450601511) 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, 3571783865 + ... + 3571783926.

It is an arithmetic number, because the mean of its divisors is an integer number (57148542336).

Almost surely, 2^221450601521 is an apocalyptic number.

It is an amenable number.

221450601521 is a deficient number, since it is larger than the sum of its proper divisors (7143567823).

221450601521 is an equidigital number, since it uses as much as digits as its factorization.

221450601521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7143567822.

The product of its (nonzero) digits is 4800, while the sum is 29.

Adding to 221450601521 its reverse (125106054122), we get a palindrome (346556655643).

The spelling of 221450601521 in words is "two hundred twenty-one billion, four hundred fifty million, six hundred one thousand, five hundred twenty-one".