39405728 has 36 divisors (see below), whose sum is σ = 82431342. Its totient is φ = 18539520.

The previous prime is 39405701. The next prime is 39405731. The reversal of 39405728 is 82750493.

It can be written as a sum of positive squares in 3 ways, for example, as 37797904 + 1607824 = 6148^2 + 1268^2 .

It is a super-2 number, since 2×39405728² = 3105622798419968, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 39405691 and 39405700.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7118 + ... + 11378.

Almost surely, 2^39405728 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 39405728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41215671).

39405728 is an abundant number, since it is smaller than the sum of its proper divisors (43025614).

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

39405728 is a wasteful number, since it uses less digits than its factorization.

39405728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4305 (or 4280 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 38.

The square root of 39405728 is about 6277.3981871473. The cubic root of 39405728 is about 340.2930806247.

The spelling of 39405728 in words is "thirty-nine million, four hundred five thousand, seven hundred twenty-eight".