661625311 has 2 divisors, whose sum is σ = 661625312. Its totient is φ = 661625310.

The previous prime is 661625267. The next prime is 661625317. The reversal of 661625311 is 113526166.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 661625311 - 2⁷ = 661625183 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661625317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330812655 + 330812656.

It is an arithmetic number, because the mean of its divisors is an integer number (330812656).

Almost surely, 2^661625311 is an apocalyptic number.

661625311 is a deficient number, since it is larger than the sum of its proper divisors (1).

661625311 is an equidigital number, since it uses as much as digits as its factorization.

661625311 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6480, while the sum is 31.

The square root of 661625311 is about 25722.0782791749. The cubic root of 661625311 is about 871.3728758161.

The spelling of 661625311 in words is "six hundred sixty-one million, six hundred twenty-five thousand, three hundred eleven".