31389128 has 8 divisors (see below), whose sum is σ = 58854630. Its totient is φ = 15694560.

The previous prime is 31389101. The next prime is 31389133. The reversal of 31389128 is 82198313.

It can be written as a sum of positive squares in only one way, i.e., 31382404 + 6724 = 5602^2 + 82^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1961813 + ... + 1961828.

Almost surely, 2^31389128 is an apocalyptic number.

It is an amenable number.

31389128 is a deficient number, since it is larger than the sum of its proper divisors (27465502).

31389128 is a wasteful number, since it uses less digits than its factorization.

31389128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3923647 (or 3923643 counting only the distinct ones).

The product of its digits is 10368, while the sum is 35.

The square root of 31389128 is about 5602.6001106629. The cubic root of 31389128 is about 315.4470112762.

The spelling of 31389128 in words is "thirty-one million, three hundred eighty-nine thousand, one hundred twenty-eight".