21481868772 has 144 divisors (see below), whose sum is σ = 67774516992. Its totient is φ = 5585690880.

The previous prime is 21481868767. The next prime is 21481868777. The reversal of 21481868772 is 27786818412.

21481868772 is a `hidden beast` number, since 2 + 1 + 481 + 86 + 87 + 7 + 2 = 666.

It is an interprime number because it is at equal distance from previous prime (21481868767) and next prime (21481868777).

It is a super-2 number, since 2×21481868772² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21481868777) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 186418 + ... + 278774.

It is an arithmetic number, because the mean of its divisors is an integer number (470656368).

Almost surely, 2^21481868772 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21481868772, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33887258496).

21481868772 is an abundant number, since it is smaller than the sum of its proper divisors (46292648220).

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

21481868772 is a wasteful number, since it uses less digits than its factorization.

21481868772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92458 (or 92453 counting only the distinct ones).

The product of its digits is 2408448, while the sum is 54.

The spelling of 21481868772 in words is "twenty-one billion, four hundred eighty-one million, eight hundred sixty-eight thousand, seven hundred seventy-two".