221421651623 has 4 divisors (see below), whose sum is σ = 221495437248. Its totient is φ = 221347866000.

The previous prime is 221421651589. The next prime is 221421651707. The reversal of 221421651623 is 326156124122.

221421651623 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 221421651623 - 2²⁴ = 221404874407 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 (221421951623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36888311 + ... + 36894312.

It is an arithmetic number, because the mean of its divisors is an integer number (55373859312).

Almost surely, 2^221421651623 is an apocalyptic number.

221421651623 is a deficient number, since it is larger than the sum of its proper divisors (73785625).

221421651623 is an equidigital number, since it uses as much as digits as its factorization.

221421651623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73785624.

The product of its digits is 34560, while the sum is 35.

Adding to 221421651623 its reverse (326156124122), we get a palindrome (547577775745).

The spelling of 221421651623 in words is "two hundred twenty-one billion, four hundred twenty-one million, six hundred fifty-one thousand, six hundred twenty-three".