21289551360 has 960 divisors, whose sum is σ = 89341781760. Its totient is φ = 4273274880.

The previous prime is 21289551347. The next prime is 21289551373. The reversal of 21289551360 is 6315598212.

It is an interprime number because it is at equal distance from previous prime (21289551347) and next prime (21289551373).

It is a tau number, because it is divible by the number of its divisors (960).

It is a super-2 number, since 2×21289551360² (a number of 21 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 153162171 + ... + 153162309.

It is an arithmetic number, because the mean of its divisors is an integer number (93064356).

Almost surely, 2^21289551360 is an apocalyptic number.

21289551360 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 21289551360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44670890880).

21289551360 is an abundant number, since it is smaller than the sum of its proper divisors (68052230400).

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

21289551360 is a wasteful number, since it uses less digits than its factorization.

21289551360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227 (or 204 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 42.

The spelling of 21289551360 in words is "twenty-one billion, two hundred eighty-nine million, five hundred fifty-one thousand, three hundred sixty".