21257485965936 has 240 divisors, whose sum is σ = 67783532469120. Its totient is φ = 6161332538880.

The previous prime is 21257485965923. The next prime is 21257485965967. The reversal of 21257485965936 is 63956958475212.

21257485965936 is a `hidden beast` number, since 2 + 1 + 2 + 5 + 7 + 485 + 96 + 59 + 3 + 6 = 666.

It is a Smith number, since the sum of its digits (72) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 384091 + ... + 6531653.

It is an arithmetic number, because the mean of its divisors is an integer number (282431385288).

Almost surely, 2^{21257485965936} 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 21257485965936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33891766234560).

21257485965936 is an abundant number, since it is smaller than the sum of its proper divisors (46526046503184).

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

21257485965936 is a wasteful number, since it uses less digits than its factorization.

21257485965936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6147684 (or 6147675 counting only the distinct ones).

The product of its digits is 979776000, while the sum is 72.

The spelling of 21257485965936 in words is "twenty-one trillion, two hundred fifty-seven billion, four hundred eighty-five million, nine hundred sixty-five thousand, nine hundred thirty-six".