221412435765621 has 4 divisors (see below), whose sum is σ = 295216581020832. Its totient is φ = 147608290510412.

The previous prime is 221412435765607. The next prime is 221412435765623. The reversal of 221412435765621 is 126567534214122.

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 221412435765621 - 2⁵ = 221412435765589 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221412435765623) 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, 36902072627601 + ... + 36902072627606.

It is an arithmetic number, because the mean of its divisors is an integer number (73804145255208).

Almost surely, 2^{221412435765621} is an apocalyptic number.

It is an amenable number.

221412435765621 is a deficient number, since it is larger than the sum of its proper divisors (73804145255211).

221412435765621 is an equidigital number, since it uses as much as digits as its factorization.

221412435765621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73804145255210.

The product of its digits is 4838400, while the sum is 51.

Adding to 221412435765621 its reverse (126567534214122), we get a palindrome (347979969979743).

The spelling of 221412435765621 in words is "two hundred twenty-one trillion, four hundred twelve billion, four hundred thirty-five million, seven hundred sixty-five thousand, six hundred twenty-one".