28861721729320 has 16 divisors (see below), whose sum is σ = 64938873891060. Its totient is φ = 11544688691712.

The previous prime is 28861721729257. The next prime is 28861721729327. The reversal of 28861721729320 is 2392712716882.

It can be written as a sum of positive squares in 2 ways, for example, as 28532840124996 + 328881604324 = 5341614^2 + 573482^2 .

It is not an unprimeable number, because it can be changed into a prime (28861721729327) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 360771521577 + ... + 360771521656.

Almost surely, 2^{28861721729320} is an apocalyptic number.

28861721729320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28861721729320 is an abundant number, since it is smaller than the sum of its proper divisors (36077152161740).

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

28861721729320 is a wasteful number, since it uses less digits than its factorization.

28861721729320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 721543043244 (or 721543043240 counting only the distinct ones).

The product of its (nonzero) digits is 8128512, while the sum is 58.

The spelling of 28861721729320 in words is "twenty-eight trillion, eight hundred sixty-one billion, seven hundred twenty-one million, seven hundred twenty-nine thousand, three hundred twenty".