66977609 has 2 divisors, whose sum is σ = 66977610. Its totient is φ = 66977608.

The previous prime is 66977591. The next prime is 66977621. The reversal of 66977609 is 90677966.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58186384 + 8791225 = 7628^2 + 2965^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66977609 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66977509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33488804 + 33488805.

It is an arithmetic number, because the mean of its divisors is an integer number (33488805).

Almost surely, 2^66977609 is an apocalyptic number.

It is an amenable number.

66977609 is a deficient number, since it is larger than the sum of its proper divisors (1).

66977609 is an equidigital number, since it uses as much as digits as its factorization.

66977609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 857304, while the sum is 50.

The square root of 66977609 is about 8183.9849095658. The cubic root of 66977609 is about 406.1095601659.

The spelling of 66977609 in words is "sixty-six million, nine hundred seventy-seven thousand, six hundred nine".