21947275586544 has 1920 divisors, whose sum is σ = 79667220971520. Its totient is φ = 5078329344000.

The previous prime is 21947275586527. The next prime is 21947275586627. The reversal of 21947275586544 is 44568557274912.

It is a Smith number, since the sum of its digits (69) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (69).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 121255666134 + ... + 121255666314.

It is an arithmetic number, because the mean of its divisors is an integer number (41493344256).

Almost surely, 2^{21947275586544} is an apocalyptic number.

21947275586544 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 21947275586544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39833610485760).

21947275586544 is an abundant number, since it is smaller than the sum of its proper divisors (57719945384976).

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

21947275586544 is a wasteful number, since it uses less digits than its factorization.

21947275586544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411 (or 394 counting only the distinct ones).

The product of its digits is 677376000, while the sum is 69.

The spelling of 21947275586544 in words is "twenty-one trillion, nine hundred forty-seven billion, two hundred seventy-five million, five hundred eighty-six thousand, five hundred forty-four".