31128143720 has 64 divisors (see below), whose sum is σ = 71595921600. Its totient is φ = 12177031680.

The previous prime is 31128143701. The next prime is 31128143731. The reversal of 31128143720 is 2734182113.

It is a super-2 number, since 2×31128143720² (a number of 22 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 330740 + ... + 414300.

It is an arithmetic number, because the mean of its divisors is an integer number (1118686275).

Almost surely, 2^31128143720 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31128143720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35797960800).

31128143720 is an abundant number, since it is smaller than the sum of its proper divisors (40467777880).

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

31128143720 is a wasteful number, since it uses less digits than its factorization.

31128143720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83778 (or 83774 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 32.

The spelling of 31128143720 in words is "thirty-one billion, one hundred twenty-eight million, one hundred forty-three thousand, seven hundred twenty".