661550671 has 2 divisors, whose sum is σ = 661550672. Its totient is φ = 661550670.

The previous prime is 661550653. The next prime is 661550689. The reversal of 661550671 is 176055166.

It is a balanced prime because it is at equal distance from previous prime (661550653) and next prime (661550689).

It is a cyclic number.

It is not a de Polignac number, because 661550671 - 2⁹ = 661550159 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661550671.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661550641) 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, 330775335 + 330775336.

It is an arithmetic number, because the mean of its divisors is an integer number (330775336).

Almost surely, 2^661550671 is an apocalyptic number.

661550671 is a deficient number, since it is larger than the sum of its proper divisors (1).

661550671 is an equidigital number, since it uses as much as digits as its factorization.

661550671 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 37800, while the sum is 37.

The square root of 661550671 is about 25720.6273446042. The cubic root of 661550671 is about 871.3401071598.

The spelling of 661550671 in words is "six hundred sixty-one million, five hundred fifty thousand, six hundred seventy-one".