21182451264 has 560 divisors, whose sum is σ = 72492900480. Its totient is φ = 6061547520.

The previous prime is 21182451247. The next prime is 21182451287. The reversal of 21182451264 is 46215428112.

21182451264 is a `hidden beast` number, since 2 + 1 + 1 + 82 + 4 + 512 + 64 = 666.

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 polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 90911692 + ... + 90911924.

It is an arithmetic number, because the mean of its divisors is an integer number (129451608).

Almost surely, 2^21182451264 is an apocalyptic number.

21182451264 is a gapful number since it is divisible by the number (24) 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 21182451264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36246450240).

21182451264 is an abundant number, since it is smaller than the sum of its proper divisors (51310449216).

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

21182451264 is a wasteful number, since it uses less digits than its factorization.

21182451264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 360 (or 341 counting only the distinct ones).

The product of its digits is 30720, while the sum is 36.

Adding to 21182451264 its reverse (46215428112), we get a palindrome (67397879376).

The spelling of 21182451264 in words is "twenty-one billion, one hundred eighty-two million, four hundred fifty-one thousand, two hundred sixty-four".