19747721448 has 384 divisors, whose sum is σ = 69708038400. Its totient is φ = 4909621248.

The previous prime is 19747721423. The next prime is 19747721503. The reversal of 19747721448 is 84412774791.

19747721448 is a `hidden beast` number, since 1 + 97 + 47 + 72 + 1 + 448 = 666.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 19747721394 and 19747721403.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 8169136 + ... + 8171552.

It is an arithmetic number, because the mean of its divisors is an integer number (181531350).

Almost surely, 2^19747721448 is an apocalyptic number.

19747721448 is a gapful number since it is divisible by the number (18) 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 19747721448, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34854019200).

19747721448 is an abundant number, since it is smaller than the sum of its proper divisors (49960316952).

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

19747721448 is a wasteful number, since it uses less digits than its factorization.

19747721448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2521 (or 2514 counting only the distinct ones).

The product of its digits is 3161088, while the sum is 54.

The spelling of 19747721448 in words is "nineteen billion, seven hundred forty-seven million, seven hundred twenty-one thousand, four hundred forty-eight".