31628725781 has 8 divisors (see below), whose sum is σ = 32096289600. Its totient is φ = 31161775680.

The previous prime is 31628725753. The next prime is 31628725819. The reversal of 31628725781 is 18752782613.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31628725781 - 2³⁰ = 30554983957 is a prime.

It is a super-2 number, since 2×31628725781² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31628725741) 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 7 ways as a sum of consecutive naturals, for example, 49076 + ... + 256253.

It is an arithmetic number, because the mean of its divisors is an integer number (4012036200).

Almost surely, 2^31628725781 is an apocalyptic number.

It is an amenable number.

31628725781 is a deficient number, since it is larger than the sum of its proper divisors (467563819).

31628725781 is a wasteful number, since it uses less digits than its factorization.

31628725781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 306859.

The product of its digits is 1128960, while the sum is 50.

The spelling of 31628725781 in words is "thirty-one billion, six hundred twenty-eight million, seven hundred twenty-five thousand, seven hundred eighty-one".