31000128880 has 40 divisors (see below), whose sum is σ = 82371772512. Its totient is φ = 10628615424.

The previous prime is 31000128871. The next prime is 31000128883. The reversal of 31000128880 is 8882100013.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×31000128880² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31000128883) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27678127 + ... + 27679246.

Almost surely, 2^31000128880 is an apocalyptic number.

It is an amenable number.

31000128880 is an abundant number, since it is smaller than the sum of its proper divisors (51371643632).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31000128880 is a wasteful number, since it uses less digits than its factorization.

31000128880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55357393 (or 55357387 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 31.

Adding to 31000128880 its reverse (8882100013), we get a palindrome (39882228893).

The spelling of 31000128880 in words is "thirty-one billion, one hundred twenty-eight thousand, eight hundred eighty".