221421551551 has 2 divisors, whose sum is σ = 221421551552. Its totient is φ = 221421551550.

The previous prime is 221421551437. The next prime is 221421551557. The reversal of 221421551551 is 155155124122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221421551551 - 2⁷ = 221421551423 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221421551557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110710775775 + 110710775776.

It is an arithmetic number, because the mean of its divisors is an integer number (110710775776).

Almost surely, 2^221421551551 is an apocalyptic number.

221421551551 is a deficient number, since it is larger than the sum of its proper divisors (1).

221421551551 is an equidigital number, since it uses as much as digits as its factorization.

221421551551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20000, while the sum is 34.

Adding to 221421551551 its reverse (155155124122), we get a palindrome (376576675673).

The spelling of 221421551551 in words is "two hundred twenty-one billion, four hundred twenty-one million, five hundred fifty-one thousand, five hundred fifty-one".