21257114720 has 96 divisors (see below), whose sum is σ = 51146756640. Its totient is φ = 8346357760.

The previous prime is 21257114719. The next prime is 21257114743. The reversal of 21257114720 is 2741175212.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8881844 + ... + 8884236.

It is an arithmetic number, because the mean of its divisors is an integer number (532778715).

Almost surely, 2^21257114720 is an apocalyptic number.

21257114720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21257114720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25573378320).

21257114720 is an abundant number, since it is smaller than the sum of its proper divisors (29889641920).

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

21257114720 is a wasteful number, since it uses less digits than its factorization.

21257114720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3408 (or 3400 counting only the distinct ones).

The product of its (nonzero) digits is 7840, while the sum is 32.

Adding to 21257114720 its reverse (2741175212), we get a palindrome (23998289932).

The spelling of 21257114720 in words is "twenty-one billion, two hundred fifty-seven million, one hundred fourteen thousand, seven hundred twenty".