39128781 has 16 divisors (see below), whose sum is σ = 55617408. Its totient is φ = 24384000.

The previous prime is 39128777. The next prime is 39128807. The reversal of 39128781 is 18782193.

39128781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 39128781 - 2² = 39128777 is a prime.

It is a super-2 number, since 2×39128781² = 3062123005091922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39128701) 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 15 ways as a sum of consecutive naturals, for example, 5161 + ... + 10241.

It is an arithmetic number, because the mean of its divisors is an integer number (3476088).

Almost surely, 2^39128781 is an apocalyptic number.

It is an amenable number.

39128781 is a deficient number, since it is larger than the sum of its proper divisors (16488627).

39128781 is a wasteful number, since it uses less digits than its factorization.

39128781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5252.

The product of its digits is 24192, while the sum is 39.

The square root of 39128781 is about 6255.3002326027. The cubic root of 39128781 is about 339.4940022351.

The spelling of 39128781 in words is "thirty-nine million, one hundred twenty-eight thousand, seven hundred eighty-one".