661207663 has 2 divisors, whose sum is σ = 661207664. Its totient is φ = 661207662.

The previous prime is 661207637. The next prime is 661207691. The reversal of 661207663 is 366702166.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661207663 is a prime.

It is equal to p_34345756 and since 661207663 and 34345756 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661207693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330603831 + 330603832.

It is an arithmetic number, because the mean of its divisors is an integer number (330603832).

Almost surely, 2^661207663 is an apocalyptic number.

661207663 is a deficient number, since it is larger than the sum of its proper divisors (1).

661207663 is an equidigital number, since it uses as much as digits as its factorization.

661207663 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432, while the sum is 37.

The square root of 661207663 is about 25713.9585245057. The cubic root of 661207663 is about 871.1894871542.

The spelling of 661207663 in words is "six hundred sixty-one million, two hundred seven thousand, six hundred sixty-three".