19215504400 has 135 divisors (see below), whose sum is σ = 48012935191. Its totient is φ = 7390109440.

The previous prime is 19215504389. The next prime is 19215504401. The reversal of 19215504400 is 440551291.

The square root of 19215504400 is 138620.

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 264127504 + 18951376896 = 16252^2 + 137664^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19215504401) 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, 80399481 + ... + 80399719.

Almost surely, 2^19215504400 is an apocalyptic number.

19215504400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19215504400 is the 138620-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19215504400

19215504400 is an abundant number, since it is smaller than the sum of its proper divisors (28797430791).

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

19215504400 is an equidigital number, since it uses as much as digits as its factorization.

19215504400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 554 (or 275 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 31.

The spelling of 19215504400 in words is "nineteen billion, two hundred fifteen million, five hundred four thousand, four hundred".