28505773840 has 40 divisors (see below), whose sum is σ = 68067172440. Its totient is φ = 11094137856.

The previous prime is 28505773819. The next prime is 28505773847. The reversal of 28505773840 is 4837750582.

It can be written as a sum of positive squares in 4 ways, for example, as 6960231184 + 21545542656 = 83428^2 + 146784^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a hoax number, since the sum of its digits (49) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (28505773847) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4812205 + ... + 4818124.

It is an arithmetic number, because the mean of its divisors is an integer number (1701679311).

Almost surely, 2^28505773840 is an apocalyptic number.

28505773840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28505773840 is an abundant number, since it is smaller than the sum of its proper divisors (39561398600).

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

28505773840 is a wasteful number, since it uses less digits than its factorization.

28505773840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9630379 (or 9630373 counting only the distinct ones).

The product of its (nonzero) digits is 1881600, while the sum is 49.

The spelling of 28505773840 in words is "twenty-eight billion, five hundred five million, seven hundred seventy-three thousand, eight hundred forty".