28970640 has 60 divisors (see below), whose sum is σ = 97295484. Its totient is φ = 7725312.

The previous prime is 28970633. The next prime is 28970653. The reversal of 28970640 is 4607982.

28970640 is a `hidden beast` number, since 2 + 8 + 9 + 7 + 0 + 640 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 16353936 + 12616704 = 4044^2 + 3552^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 28970595 and 28970604.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19399 + ... + 20838.

Almost surely, 2^28970640 is an apocalyptic number.

28970640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28970640 is an abundant number, since it is smaller than the sum of its proper divisors (68324844).

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

28970640 is a wasteful number, since it uses less digits than its factorization.

28970640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40256 (or 40247 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 28970640 is about 5382.4381092587. The cubic root of 28970640 is about 307.1279656949.

The spelling of 28970640 in words is "twenty-eight million, nine hundred seventy thousand, six hundred forty".