21175385028 has 48 divisors (see below), whose sum is σ = 59789326464. Its totient is φ = 5694220800.

The previous prime is 21175385027. The next prime is 21175385057. The reversal of 21175385028 is 82058357112.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (21175385027) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 7412923 + ... + 7415778.

It is an arithmetic number, because the mean of its divisors is an integer number (1245610968).

Almost surely, 2^21175385028 is an apocalyptic number.

21175385028 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21175385028 is an abundant number, since it is smaller than the sum of its proper divisors (38613941436).

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

21175385028 is a wasteful number, since it uses less digits than its factorization.

21175385028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14828732 (or 14828730 counting only the distinct ones).

The product of its (nonzero) digits is 134400, while the sum is 42.

The spelling of 21175385028 in words is "twenty-one billion, one hundred seventy-five million, three hundred eighty-five thousand, twenty-eight".