66990919 has 2 divisors, whose sum is σ = 66990920. Its totient is φ = 66990918.

The previous prime is 66990893. The next prime is 66990943. The reversal of 66990919 is 91909966.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66990919 - 2¹¹ = 66988871 is a prime.

It is a super-2 number, since 2×66990919² = 8975566456929122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66993919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33495459 + 33495460.

It is an arithmetic number, because the mean of its divisors is an integer number (33495460).

Almost surely, 2^66990919 is an apocalyptic number.

66990919 is a deficient number, since it is larger than the sum of its proper divisors (1).

66990919 is an equidigital number, since it uses as much as digits as its factorization.

66990919 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 236196, while the sum is 49.

The square root of 66990919 is about 8184.7980427131. The cubic root of 66990919 is about 406.1364595049.

The spelling of 66990919 in words is "sixty-six million, nine hundred ninety thousand, nine hundred nineteen".