66998783 has 2 divisors, whose sum is σ = 66998784. Its totient is φ = 66998782.

The previous prime is 66998761. The next prime is 66998809. The reversal of 66998783 is 38789966.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66998783 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66998713) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33499391 + 33499392.

It is an arithmetic number, because the mean of its divisors is an integer number (33499392).

Almost surely, 2^66998783 is an apocalyptic number.

66998783 is a deficient number, since it is larger than the sum of its proper divisors (1).

66998783 is an equidigital number, since it uses as much as digits as its factorization.

66998783 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3919104, while the sum is 56.

The square root of 66998783 is about 8185.2784314280. The cubic root of 66998783 is about 406.1523508734.

The spelling of 66998783 in words is "sixty-six million, nine hundred ninety-eight thousand, seven hundred eighty-three".