66719491 has 2 divisors, whose sum is σ = 66719492. Its totient is φ = 66719490.

The previous prime is 66719453. The next prime is 66719551. The reversal of 66719491 is 19491766.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66719491 - 2⁷ = 66719363 is a prime.

It is not a weakly prime, because it can be changed into another prime (66719291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33359745 + 33359746.

It is an arithmetic number, because the mean of its divisors is an integer number (33359746).

Almost surely, 2^66719491 is an apocalyptic number.

66719491 is a deficient number, since it is larger than the sum of its proper divisors (1).

66719491 is an equidigital number, since it uses as much as digits as its factorization.

66719491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 81648, while the sum is 43.

The square root of 66719491 is about 8168.1999853089. The cubic root of 66719491 is about 405.5872008528.

The spelling of 66719491 in words is "sixty-six million, seven hundred nineteen thousand, four hundred ninety-one".