31628566661 has 4 divisors (see below), whose sum is σ = 31760904000. Its totient is φ = 31496229324.

The previous prime is 31628566649. The next prime is 31628566681. The reversal of 31628566661 is 16666582613.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31628566661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31628566601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66168311 + ... + 66168788.

It is an arithmetic number, because the mean of its divisors is an integer number (7940226000).

Almost surely, 2^31628566661 is an apocalyptic number.

It is an amenable number.

31628566661 is a deficient number, since it is larger than the sum of its proper divisors (132337339).

31628566661 is a wasteful number, since it uses less digits than its factorization.

31628566661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132337338.

The product of its digits is 1866240, while the sum is 50.

The spelling of 31628566661 in words is "thirty-one billion, six hundred twenty-eight million, five hundred sixty-six thousand, six hundred sixty-one".