19221385008400 has 135 divisors (see below), whose sum is σ = 47833007844271. Its totient is φ = 7422449386240.

The previous prime is 19221385008323. The next prime is 19221385008407. The reversal of 19221385008400 is 480058312291.

The square root of 19221385008400 is 4384220.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 264208336144 + 18957176672256 = 514012^2 + 4353984^2 .

It is a super-2 number, since 2×19221385008400² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19221385008407) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2542843821 + ... + 2542851379.

Almost surely, 2^{19221385008400} is an apocalyptic number.

19221385008400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19221385008400 is the 4384220-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19221385008400

19221385008400 is an abundant number, since it is smaller than the sum of its proper divisors (28611622835871).

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

19221385008400 is an frugal number, since it uses more digits than its factorization.

19221385008400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15194 (or 7595 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 43.

The spelling of 19221385008400 in words is "nineteen trillion, two hundred twenty-one billion, three hundred eighty-five million, eight thousand, four hundred".