66719551 has 2 divisors, whose sum is σ = 66719552. Its totient is φ = 66719550.

The previous prime is 66719491. The next prime is 66719557. The reversal of 66719551 is 15591766.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66719551 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66719557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33359775 + 33359776.

It is an arithmetic number, because the mean of its divisors is an integer number (33359776).

Almost surely, 2^66719551 is an apocalyptic number.

66719551 is a deficient number, since it is larger than the sum of its proper divisors (1).

66719551 is an equidigital number, since it uses as much as digits as its factorization.

66719551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56700, while the sum is 40.

The square root of 66719551 is about 8168.2036580879. The cubic root of 66719551 is about 405.5873224326.

The spelling of 66719551 in words is "sixty-six million, seven hundred nineteen thousand, five hundred fifty-one".