21502745460 has 384 divisors, whose sum is σ = 82615680000. Its totient is φ = 4625123328.

The previous prime is 21502745441. The next prime is 21502745497. The reversal of 21502745460 is 6454720512.

It is a happy number.

21502745460 is a `hidden beast` number, since 2 + 150 + 2 + 7 + 45 + 460 = 666.

It is a super-2 number, since 2×21502745460² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

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 127 ways as a sum of consecutive naturals, for example, 3145326 + ... + 3152154.

It is an arithmetic number, because the mean of its divisors is an integer number (215145000).

Almost surely, 2^21502745460 is an apocalyptic number.

21502745460 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 21502745460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41307840000).

21502745460 is an abundant number, since it is smaller than the sum of its proper divisors (61112934540).

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

21502745460 is a wasteful number, since it uses less digits than its factorization.

21502745460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6885 (or 6863 counting only the distinct ones).

The product of its (nonzero) digits is 67200, while the sum is 36.

The spelling of 21502745460 in words is "twenty-one billion, five hundred two million, seven hundred forty-five thousand, four hundred sixty".