21540854461672 has 144 divisors (see below), whose sum is σ = 51957805700160. Its totient is φ = 8340343659648.

The previous prime is 21540854461601. The next prime is 21540854461771. The reversal of 21540854461672 is 27616445804512.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 345438 + ... + 6572749.

It is an arithmetic number, because the mean of its divisors is an integer number (360818095140).

Almost surely, 2^{21540854461672} 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 21540854461672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25978902850080).

21540854461672 is an abundant number, since it is smaller than the sum of its proper divisors (30416951238488).

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

21540854461672 is a wasteful number, since it uses less digits than its factorization.

21540854461672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6918280 (or 6918256 counting only the distinct ones).

The product of its (nonzero) digits is 12902400, while the sum is 55.

The spelling of 21540854461672 in words is "twenty-one trillion, five hundred forty billion, eight hundred fifty-four million, four hundred sixty-one thousand, six hundred seventy-two".