221043551 has 2 divisors, whose sum is σ = 221043552. Its totient is φ = 221043550.

The previous prime is 221043517. The next prime is 221043583. The reversal of 221043551 is 155340122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221043551 - 2²⁶ = 153934687 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221043451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110521775 + 110521776.

It is an arithmetic number, because the mean of its divisors is an integer number (110521776).

Almost surely, 2^221043551 is an apocalyptic number.

221043551 is a deficient number, since it is larger than the sum of its proper divisors (1).

221043551 is an equidigital number, since it uses as much as digits as its factorization.

221043551 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 221043551 is about 14867.5334538046. The cubic root of 221043551 is about 604.6340714558.

Adding to 221043551 its reverse (155340122), we get a palindrome (376383673).

The spelling of 221043551 in words is "two hundred twenty-one million, forty-three thousand, five hundred fifty-one".