31129781989 has 8 divisors (see below), whose sum is σ = 31794761088. Its totient is φ = 30464913120.

The previous prime is 31129781941. The next prime is 31129781993. The reversal of 31129781989 is 98918792113.

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 31129781989 - 2²⁵ = 31096227557 is a prime.

It is a super-2 number, since 2×31129781989² (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 (31129781929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 815449 + ... + 852769.

It is an arithmetic number, because the mean of its divisors is an integer number (3974345136).

Almost surely, 2^31129781989 is an apocalyptic number.

It is an amenable number.

31129781989 is a deficient number, since it is larger than the sum of its proper divisors (664979099).

31129781989 is a wasteful number, since it uses less digits than its factorization.

31129781989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55115.

The product of its digits is 1959552, while the sum is 58.

The spelling of 31129781989 in words is "thirty-one billion, one hundred twenty-nine million, seven hundred eighty-one thousand, nine hundred eighty-nine".