21617969400 has 144 divisors (see below), whose sum is σ = 72683193960. Its totient is φ = 5758214400.

The previous prime is 21617969393. The next prime is 21617969413. The reversal of 21617969400 is 496971612.

21617969400 is a `hidden beast` number, since 2 + 16 + 179 + 69 + 400 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1687419 + ... + 1700181.

Almost surely, 2^21617969400 is an apocalyptic number.

21617969400 is a gapful number since it is divisible by the number (20) 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 21617969400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36341596980).

21617969400 is an abundant number, since it is smaller than the sum of its proper divisors (51065224560).

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

21617969400 is a wasteful number, since it uses less digits than its factorization.

21617969400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13726 (or 13714 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 45.

The spelling of 21617969400 in words is "twenty-one billion, six hundred seventeen million, nine hundred sixty-nine thousand, four hundred".