21897173376 has 384 divisors, whose sum is σ = 70929331200. Its totient is φ = 6437781504.

The previous prime is 21897173369. The next prime is 21897173377. The reversal of 21897173376 is 67337179812.

21897173376 is a `hidden beast` number, since 2 + 18 + 97 + 173 + 376 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21897173377) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 55156410 + ... + 55156806.

It is an arithmetic number, because the mean of its divisors is an integer number (184711800).

Almost surely, 2^21897173376 is an apocalyptic number.

21897173376 is a gapful number since it is divisible by the number (26) 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 21897173376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35464665600).

21897173376 is an abundant number, since it is smaller than the sum of its proper divisors (49032157824).

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

21897173376 is a wasteful number, since it uses less digits than its factorization.

21897173376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586 (or 571 counting only the distinct ones).

The product of its digits is 2667168, while the sum is 54.

The spelling of 21897173376 in words is "twenty-one billion, eight hundred ninety-seven million, one hundred seventy-three thousand, three hundred seventy-six".