661894307 has 2 divisors, whose sum is σ = 661894308. Its totient is φ = 661894306.

The previous prime is 661894301. The next prime is 661894319. The reversal of 661894307 is 703498166.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661894307 - 2⁴ = 661894291 is a prime.

It is not a weakly prime, because it can be changed into another prime (661894301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330947153 + 330947154.

It is an arithmetic number, because the mean of its divisors is an integer number (330947154).

Almost surely, 2^661894307 is an apocalyptic number.

661894307 is a deficient number, since it is larger than the sum of its proper divisors (1).

661894307 is an equidigital number, since it uses as much as digits as its factorization.

661894307 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 217728, while the sum is 44.

The square root of 661894307 is about 25727.3066409992. The cubic root of 661894307 is about 871.4909507323.

The spelling of 661894307 in words is "six hundred sixty-one million, eight hundred ninety-four thousand, three hundred seven".