216743551 has 2 divisors, whose sum is σ = 216743552. Its totient is φ = 216743550.

The previous prime is 216743543. The next prime is 216743567. The reversal of 216743551 is 155347612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 216743551 - 2³ = 216743543 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216744551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108371775 + 108371776.

It is an arithmetic number, because the mean of its divisors is an integer number (108371776).

Almost surely, 2^216743551 is an apocalyptic number.

216743551 is a deficient number, since it is larger than the sum of its proper divisors (1).

216743551 is an equidigital number, since it uses as much as digits as its factorization.

216743551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25200, while the sum is 34.

The square root of 216743551 is about 14722.2128431836. The cubic root of 216743551 is about 600.6876846634.

The spelling of 216743551 in words is "two hundred sixteen million, seven hundred forty-three thousand, five hundred fifty-one".