21658347280 has 40 divisors (see below), whose sum is σ = 50361787800. Its totient is φ = 8662284288.

The previous prime is 21658347257. The next prime is 21658347281. The reversal of 21658347280 is 8274385612.

It can be written as a sum of positive squares in 4 ways, for example, as 2228217616 + 19430129664 = 47204^2 + 139392^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 21658347280.

It is not an unprimeable number, because it can be changed into a prime (21658347281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1236826 + ... + 1254214.

It is an arithmetic number, because the mean of its divisors is an integer number (1259044695).

Almost surely, 2^21658347280 is an apocalyptic number.

21658347280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21658347280 is an abundant number, since it is smaller than the sum of its proper divisors (28703440520).

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

21658347280 is a wasteful number, since it uses less digits than its factorization.

21658347280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32971 (or 32965 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 46.

The spelling of 21658347280 in words is "twenty-one billion, six hundred fifty-eight million, three hundred forty-seven thousand, two hundred eighty".