21255361512 has 160 divisors (see below), whose sum is σ = 67628688480. Its totient is φ = 5520708480.

The previous prime is 21255361507. The next prime is 21255361531. The reversal of 21255361512 is 21516355212.

It is a super-2 number, since 2×21255361512² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 617098 + ... + 650630.

It is an arithmetic number, because the mean of its divisors is an integer number (422679303).

Almost surely, 2^21255361512 is an apocalyptic number.

21255361512 is a gapful number since it is divisible by the number (22) 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 21255361512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33814344240).

21255361512 is an abundant number, since it is smaller than the sum of its proper divisors (46373326968).

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

21255361512 is a wasteful number, since it uses less digits than its factorization.

21255361512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33581 (or 33556 counting only the distinct ones).

The product of its digits is 18000, while the sum is 33.

The spelling of 21255361512 in words is "twenty-one billion, two hundred fifty-five million, three hundred sixty-one thousand, five hundred twelve".