28720660055544 has 48 divisors (see below), whose sum is σ = 77786751505320. Its totient is φ = 9573352672320.

The previous prime is 28720660055491. The next prime is 28720660055569. The reversal of 28720660055544 is 44555006602782.

28720660055544 is a `hidden beast` number, since 2 + 8 + 7 + 20 + 6 + 60 + 0 + 5 + 554 + 4 = 666.

It is a super-2 number, since 2×28720660055544² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 702202 + ... + 7611465.

Almost surely, 2^{28720660055544} is an apocalyptic number.

28720660055544 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

28720660055544 is an abundant number, since it is smaller than the sum of its proper divisors (49066091449776).

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

28720660055544 is a wasteful number, since it uses less digits than its factorization.

28720660055544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8361660 (or 8361653 counting only the distinct ones).

The product of its (nonzero) digits is 16128000, while the sum is 54.

The spelling of 28720660055544 in words is "twenty-eight trillion, seven hundred twenty billion, six hundred sixty million, fifty-five thousand, five hundred forty-four".