661501369 has 2 divisors, whose sum is σ = 661501370. Its totient is φ = 661501368.

The previous prime is 661501363. The next prime is 661501387. The reversal of 661501369 is 963105166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 656025769 + 5475600 = 25613^2 + 2340^2 .

It is a cyclic number.

It is not a de Polignac number, because 661501369 - 2³ = 661501361 is a prime.

It is a super-2 number, since 2×661501369² = 875168122377748322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (661501361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330750684 + 330750685.

It is an arithmetic number, because the mean of its divisors is an integer number (330750685).

Almost surely, 2^661501369 is an apocalyptic number.

It is an amenable number.

661501369 is a deficient number, since it is larger than the sum of its proper divisors (1).

661501369 is an equidigital number, since it uses as much as digits as its factorization.

661501369 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 29160, while the sum is 37.

The square root of 661501369 is about 25719.6689131101. The cubic root of 661501369 is about 871.3184611096.

The spelling of 661501369 in words is "six hundred sixty-one million, five hundred one thousand, three hundred sixty-nine".