66216499 has 2 divisors, whose sum is σ = 66216500. Its totient is φ = 66216498.

The previous prime is 66216461. The next prime is 66216511. The reversal of 66216499 is 99461266.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66216499 - 2¹⁵ = 66183731 is a prime.

It is not a weakly prime, because it can be changed into another prime (66210499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33108249 + 33108250.

It is an arithmetic number, because the mean of its divisors is an integer number (33108250).

Almost surely, 2^66216499 is an apocalyptic number.

66216499 is a deficient number, since it is larger than the sum of its proper divisors (1).

66216499 is an equidigital number, since it uses as much as digits as its factorization.

66216499 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 43.

The square root of 66216499 is about 8137.3520877494. The cubic root of 66216499 is about 404.5654007970.

It can be divided in two parts, 662 and 16499, that added together give a square (17161 = 131²).

The spelling of 66216499 in words is "sixty-six million, two hundred sixteen thousand, four hundred ninety-nine".