21257883456 has 224 divisors, whose sum is σ = 60675194880. Its totient is φ = 6553344000.

The previous prime is 21257883419. The next prime is 21257883463. The reversal of 21257883456 is 65438875212.

It is a junction number, because it is equal to n+sod(n) for n = 21257883399 and 21257883408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18468481 + ... + 18469631.

Almost surely, 2^21257883456 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 21257883456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30337597440).

21257883456 is an abundant number, since it is smaller than the sum of its proper divisors (39417311424).

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

21257883456 is a wasteful number, since it uses less digits than its factorization.

21257883456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1333 (or 1323 counting only the distinct ones).

The product of its digits is 3225600, while the sum is 51.

The spelling of 21257883456 in words is "twenty-one billion, two hundred fifty-seven million, eight hundred eighty-three thousand, four hundred fifty-six".