28914025581 has 48 divisors (see below), whose sum is σ = 50299741440. Its totient is φ = 15647385600.

The previous prime is 28914025541. The next prime is 28914025583. The reversal of 28914025581 is 18552041982.

28914025581 is a `hidden beast` number, since 2 + 8 + 9 + 1 + 40 + 25 + 581 = 666.

It is not a de Polignac number, because 28914025581 - 2¹⁷ = 28913894509 is a prime.

It is a super-2 number, since 2×28914025581² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28914025583) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 47565 + ... + 245133.

It is an arithmetic number, because the mean of its divisors is an integer number (1047911280).

Almost surely, 2^28914025581 is an apocalyptic number.

28914025581 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28914025581 is a deficient number, since it is larger than the sum of its proper divisors (21385715859).

28914025581 is a wasteful number, since it uses less digits than its factorization.

28914025581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197706 (or 197703 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 45.

It can be divided in two parts, 289140 and 25581, that added together give a square (314721 = 561²).

The spelling of 28914025581 in words is "twenty-eight billion, nine hundred fourteen million, twenty-five thousand, five hundred eighty-one".