66697951 has 2 divisors, whose sum is σ = 66697952. Its totient is φ = 66697950.

The previous prime is 66697937. The next prime is 66697991. The reversal of 66697951 is 15979666.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66697951 - 2⁷ = 66697823 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66697895 and 66697904.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66697991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33348975 + 33348976.

It is an arithmetic number, because the mean of its divisors is an integer number (33348976).

Almost surely, 2^66697951 is an apocalyptic number.

66697951 is a deficient number, since it is larger than the sum of its proper divisors (1).

66697951 is an equidigital number, since it uses as much as digits as its factorization.

66697951 is an evil number, because the sum of its binary digits is even.

The product of its digits is 612360, while the sum is 49.

The square root of 66697951 is about 8166.8813509197. The cubic root of 66697951 is about 405.5435489978.

The spelling of 66697951 in words is "sixty-six million, six hundred ninety-seven thousand, nine hundred fifty-one".