28811961972 has 36 divisors (see below), whose sum is σ = 74204397540. Its totient is φ = 9422779392.

The previous prime is 28811961923. The next prime is 28811961991. The reversal of 28811961972 is 27916911882.

It is a happy number.

28811961972 is a `hidden beast` number, since 2 + 8 + 8 + 1 + 19 + 619 + 7 + 2 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 20035270116 + 8776691856 = 141546^2 + 93684^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7548397 + ... + 7552212.

It is an arithmetic number, because the mean of its divisors is an integer number (2061233265).

Almost surely, 2^28811961972 is an apocalyptic number.

It is an amenable number.

28811961972 is an abundant number, since it is smaller than the sum of its proper divisors (45392435568).

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

28811961972 is a wasteful number, since it uses less digits than its factorization.

28811961972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15100672 (or 15100667 counting only the distinct ones).

The product of its digits is 870912, while the sum is 54.

The spelling of 28811961972 in words is "twenty-eight billion, eight hundred eleven million, nine hundred sixty-one thousand, nine hundred seventy-two".