28721576420 has 24 divisors (see below), whose sum is σ = 61337606400. Its totient is φ = 11293907552.

The previous prime is 28721576371. The next prime is 28721576431. The reversal of 28721576420 is 2467512782.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12168980 + ... + 12171339.

It is an arithmetic number, because the mean of its divisors is an integer number (2555733600).

Almost surely, 2^28721576420 is an apocalyptic number.

28721576420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28721576420 is an abundant number, since it is smaller than the sum of its proper divisors (32616029980).

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

28721576420 is a wasteful number, since it uses less digits than its factorization.

28721576420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24340387 (or 24340385 counting only the distinct ones).

The product of its (nonzero) digits is 376320, while the sum is 44.

The spelling of 28721576420 in words is "twenty-eight billion, seven hundred twenty-one million, five hundred seventy-six thousand, four hundred twenty".