19785344400 has 90 divisors (see below), whose sum is σ = 68660653490. Its totient is φ = 5276090880.

The previous prime is 19785344339. The next prime is 19785344401. The reversal of 19785344400 is 444358791.

19785344400 is a `hidden beast` number, since 1 + 9 + 78 + 534 + 4 + 40 + 0 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 2359296 + 19782985104 = 1536^2 + 140652^2 .

It is a tau number, because it is divible by the number of its divisors (90).

It is a super-2 number, since 2×19785344400² (a number of 21 digits) contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (19785344401) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 2744365 + ... + 2751564.

Almost surely, 2^19785344400 is an apocalyptic number.

19785344400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19785344400 is an abundant number, since it is smaller than the sum of its proper divisors (48875309090).

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

19785344400 is a wasteful number, since it uses less digits than its factorization.

19785344400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5495953 (or 5495939 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 45.

The spelling of 19785344400 in words is "nineteen billion, seven hundred eighty-five million, three hundred forty-four thousand, four hundred".