21259783260 has 192 divisors, whose sum is σ = 69122457600. Its totient is φ = 5486045760.

The previous prime is 21259783219. The next prime is 21259783267. The reversal of 21259783260 is 6238795212.

21259783260 is a `hidden beast` number, since 2 + 1 + 259 + 78 + 326 + 0 = 666.

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 (21259783267) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1348101 + ... + 1363779.

It is an arithmetic number, because the mean of its divisors is an integer number (360012800).

Almost surely, 2^21259783260 is an apocalyptic number.

21259783260 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 21259783260, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34561228800).

21259783260 is an abundant number, since it is smaller than the sum of its proper divisors (47862674340).

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

21259783260 is a wasteful number, since it uses less digits than its factorization.

21259783260 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15740 (or 15720 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 21259783260 in words is "twenty-one billion, two hundred fifty-nine million, seven hundred eighty-three thousand, two hundred sixty".