19819742400 has 252 divisors, whose sum is σ = 74588732712. Its totient is φ = 4974305280.

The previous prime is 19819742389. The next prime is 19819742407. The reversal of 19819742400 is 424791891.

It is a happy number.

19819742400 is a `hidden beast` number, since 19 + 8 + 197 + 42 + 400 = 666.

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 (19819742407) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 204319 + ... + 285281.

Almost surely, 2^19819742400 is an apocalyptic number.

19819742400 is a gapful number since it is divisible by the number (10) 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 19819742400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37294366356).

19819742400 is an abundant number, since it is smaller than the sum of its proper divisors (54768990312).

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

19819742400 is a wasteful number, since it uses less digits than its factorization.

19819742400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81008 (or 80990 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The spelling of 19819742400 in words is "nineteen billion, eight hundred nineteen million, seven hundred forty-two thousand, four hundred".