28071640 has 16 divisors (see below), whose sum is σ = 63161280. Its totient is φ = 11228640.

The previous prime is 28071613. The next prime is 28071653. The reversal of 28071640 is 4617082.

28071640 = 1361² + 1362² + ... + 1375².

It is a junction number, because it is equal to n+sod(n) for n = 28071599 and 28071608.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 350856 + ... + 350935.

It is an arithmetic number, because the mean of its divisors is an integer number (3947580).

Almost surely, 2^28071640 is an apocalyptic number.

28071640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28071640 is an abundant number, since it is smaller than the sum of its proper divisors (35089640).

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

28071640 is a wasteful number, since it uses less digits than its factorization.

28071640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 701802 (or 701798 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 28071640 is about 5298.2676414088. The cubic root of 28071640 is about 303.9176542895.

The spelling of 28071640 in words is "twenty-eight million, seventy-one thousand, six hundred forty".