661386727 has 2 divisors, whose sum is σ = 661386728. Its totient is φ = 661386726.

The previous prime is 661386709. The next prime is 661386763. The reversal of 661386727 is 727683166.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661386727 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661386707) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330693363 + 330693364.

It is an arithmetic number, because the mean of its divisors is an integer number (330693364).

Almost surely, 2^661386727 is an apocalyptic number.

661386727 is a deficient number, since it is larger than the sum of its proper divisors (1).

661386727 is an equidigital number, since it uses as much as digits as its factorization.

661386727 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 508032, while the sum is 46.

The square root of 661386727 is about 25717.4401331081. The cubic root of 661386727 is about 871.2681233644.

The spelling of 661386727 in words is "six hundred sixty-one million, three hundred eighty-six thousand, seven hundred twenty-seven".