31380128 has 48 divisors (see below), whose sum is σ = 67021416. Its totient is φ = 14376960.

The previous prime is 31380127. The next prime is 31380197. The reversal of 31380128 is 82108313.

It can be written as a sum of positive squares in 4 ways, for example, as 14961424 + 16418704 = 3868^2 + 4052^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a junction number, because it is equal to n+sod(n) for n = 31380097 and 31380106.

It is not an unprimeable number, because it can be changed into a prime (31380121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 100100 + ... + 100412.

Almost surely, 2^31380128 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 31380128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33510708).

31380128 is an abundant number, since it is smaller than the sum of its proper divisors (35641288).

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

31380128 is a wasteful number, since it uses less digits than its factorization.

31380128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 577 (or 569 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 31380128 is about 5601.7968545816. The cubic root of 31380128 is about 315.4168597061.

It can be divided in two parts, 313 and 80128, that multiplied together give a square (25080064 = 5008²).

The spelling of 31380128 in words is "thirty-one million, three hundred eighty thousand, one hundred twenty-eight".