66621767 has 2 divisors, whose sum is σ = 66621768. Its totient is φ = 66621766.

The previous prime is 66621713. The next prime is 66621769. The reversal of 66621767 is 76712666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66621767 - 2¹² = 66617671 is a prime.

Together with 66621769, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66621769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33310883 + 33310884.

It is an arithmetic number, because the mean of its divisors is an integer number (33310884).

Almost surely, 2^66621767 is an apocalyptic number.

66621767 is a deficient number, since it is larger than the sum of its proper divisors (1).

66621767 is an equidigital number, since it uses as much as digits as its factorization.

66621767 is an evil number, because the sum of its binary digits is even.

The product of its digits is 127008, while the sum is 41.

The square root of 66621767 is about 8162.2158143485. The cubic root of 66621767 is about 405.3890829805.

The spelling of 66621767 in words is "sixty-six million, six hundred twenty-one thousand, seven hundred sixty-seven".