28773447981 has 16 divisors (see below), whose sum is σ = 41068262400. Its totient is φ = 17864689968.

The previous prime is 28773447977. The next prime is 28773448031. The reversal of 28773447981 is 18974437782.

It is not a de Polignac number, because 28773447981 - 2² = 28773447977 is a prime.

It is a super-2 number, since 2×28773447981² (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 (28773447931) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4274581 + ... + 4281306.

It is an arithmetic number, because the mean of its divisors is an integer number (2566766400).

Almost surely, 2^28773447981 is an apocalyptic number.

It is an amenable number.

28773447981 is a deficient number, since it is larger than the sum of its proper divisors (12294814419).

28773447981 is a wasteful number, since it uses less digits than its factorization.

28773447981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8555968.

The product of its digits is 18966528, while the sum is 60.

The spelling of 28773447981 in words is "twenty-eight billion, seven hundred seventy-three million, four hundred forty-seven thousand, nine hundred eighty-one".