21286963440 has 240 divisors, whose sum is σ = 78137070336. Its totient is φ = 5170176000.

The previous prime is 21286963433. The next prime is 21286963441. The reversal of 21286963440 is 4436968212.

21286963440 is a `hidden beast` number, since 2 + 1 + 2 + 8 + 6 + 9 + 634 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21286963441) 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 47 ways as a sum of consecutive naturals, for example, 351390 + ... + 407490.

Almost surely, 2^21286963440 is an apocalyptic number.

21286963440 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 21286963440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39068535168).

21286963440 is an abundant number, since it is smaller than the sum of its proper divisors (56850106896).

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

21286963440 is a wasteful number, since it uses less digits than its factorization.

21286963440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56168 (or 56159 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 45.

The spelling of 21286963440 in words is "twenty-one billion, two hundred eighty-six million, nine hundred sixty-three thousand, four hundred forty".