28691389440 has 792 divisors, whose sum is σ = 117730044432. Its totient is φ = 6440878080.

The previous prime is 28691389429. The next prime is 28691389459. The reversal of 28691389440 is 4498319682.

28691389440 is a `hidden beast` number, since 2 + 8 + 69 + 138 + 9 + 440 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 219018175 + ... + 219018305.

It is an arithmetic number, because the mean of its divisors is an integer number (148649046).

Almost surely, 2^28691389440 is an apocalyptic number.

28691389440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28691389440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (58865022216).

28691389440 is an abundant number, since it is smaller than the sum of its proper divisors (89038654992).

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

28691389440 is a wasteful number, since it uses less digits than its factorization.

28691389440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273 (or 245 counting only the distinct ones).

The product of its (nonzero) digits is 2985984, while the sum is 54.

The spelling of 28691389440 in words is "twenty-eight billion, six hundred ninety-one million, three hundred eighty-nine thousand, four hundred forty".