21249249357056 has 216 divisors, whose sum is σ = 51341105007360. Its totient is φ = 8744875216896.

The previous prime is 21249249357053. The next prime is 21249249357179. The reversal of 21249249357056 is 65075394294212.

It is a junction number, because it is equal to n+sod(n) for n = 21249249356986 and 21249249357004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21249249357053) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 30907085 + ... + 31587123.

It is an arithmetic number, because the mean of its divisors is an integer number (237690300960).

Almost surely, 2^{21249249357056} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21249249357056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25670552503680).

21249249357056 is an abundant number, since it is smaller than the sum of its proper divisors (30091855650304).

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

21249249357056 is an equidigital number, since it uses as much as digits as its factorization.

21249249357056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 680169 (or 680148 counting only the distinct ones).

The product of its (nonzero) digits is 32659200, while the sum is 59.

The spelling of 21249249357056 in words is "twenty-one trillion, two hundred forty-nine billion, two hundred forty-nine million, three hundred fifty-seven thousand, fifty-six".