21355066240 has 32 divisors (see below), whose sum is σ = 51051956760. Its totient is φ = 8542026240.

The previous prime is 21355066223. The next prime is 21355066247. The reversal of 21355066240 is 4266055312.

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×21355066240² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21355066196 and 21355066205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21355066247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16683006 + ... + 16684285.

Almost surely, 2^21355066240 is an apocalyptic number.

21355066240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21355066240 is an abundant number, since it is smaller than the sum of its proper divisors (29696890520).

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

21355066240 is an equidigital number, since it uses as much as digits as its factorization.

21355066240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33367310 (or 33367298 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 34.

The spelling of 21355066240 in words is "twenty-one billion, three hundred fifty-five million, sixty-six thousand, two hundred forty".