667591601 has 2 divisors, whose sum is σ = 667591602. Its totient is φ = 667591600.

The previous prime is 667591579. The next prime is 667591621. The reversal of 667591601 is 106195766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 339112225 + 328479376 = 18415^2 + 18124^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-667591601 is a prime.

It is not a weakly prime, because it can be changed into another prime (667591621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333795800 + 333795801.

It is an arithmetic number, because the mean of its divisors is an integer number (333795801).

Almost surely, 2^667591601 is an apocalyptic number.

It is an amenable number.

667591601 is a deficient number, since it is larger than the sum of its proper divisors (1).

667591601 is an equidigital number, since it uses as much as digits as its factorization.

667591601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 68040, while the sum is 41.

The square root of 667591601 is about 25837.7940428358. The cubic root of 667591601 is about 873.9842803248.

The spelling of 667591601 in words is "six hundred sixty-seven million, five hundred ninety-one thousand, six hundred one".