28531145658880 has 80 divisors (see below), whose sum is σ = 68565868237944. Its totient is φ = 11386101104640.

The previous prime is 28531145658859. The next prime is 28531145658881. The reversal of 28531145658880 is 8885654113582.

It can be written as a sum of positive squares in 4 ways, for example, as 21527966750976 + 7003178907904 = 4639824^2 + 2646352^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (64).

It is not an unprimeable number, because it can be changed into a prime (28531145658881) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11761011 + ... + 13977970.

Almost surely, 2^{28531145658880} is an apocalyptic number.

28531145658880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28531145658880 is an abundant number, since it is smaller than the sum of its proper divisors (40034722579064).

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

28531145658880 is an equidigital number, since it uses as much as digits as its factorization.

28531145658880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25739437 (or 25739421 counting only the distinct ones).

The product of its (nonzero) digits is 73728000, while the sum is 64.

The spelling of 28531145658880 in words is "twenty-eight trillion, five hundred thirty-one billion, one hundred forty-five million, six hundred fifty-eight thousand, eight hundred eighty".