28778645575 has 24 divisors (see below), whose sum is σ = 36501855200. Its totient is φ = 22501065600.

The previous prime is 28778645569. The next prime is 28778645579. The reversal of 28778645575 is 57554687782.

It is not a de Polignac number, because 28778645575 - 2⁷ = 28778645447 is a prime.

It is a super-2 number, since 2×28778645575² (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 (28778645579) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 179326 + ... + 299524.

Almost surely, 2^28778645575 is an apocalyptic number.

28778645575 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

28778645575 is a deficient number, since it is larger than the sum of its proper divisors (7723209625).

28778645575 is a wasteful number, since it uses less digits than its factorization.

28778645575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120427 (or 120422 counting only the distinct ones).

The product of its digits is 131712000, while the sum is 64.

The spelling of 28778645575 in words is "twenty-eight billion, seven hundred seventy-eight million, six hundred forty-five thousand, five hundred seventy-five".