19749051840 has 224 divisors, whose sum is σ = 71749822464. Its totient is φ = 4508467200.

The previous prime is 19749051787. The next prime is 19749051841. The reversal of 19749051840 is 4815094791.

It is a tau number, because it is divible by the number of its divisors (224).

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 19749051840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19749051841) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8069497 + ... + 8071943.

Almost surely, 2^19749051840 is an apocalyptic number.

19749051840 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 19749051840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35874911232).

19749051840 is an abundant number, since it is smaller than the sum of its proper divisors (52000770624).

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

19749051840 is a wasteful number, since it uses less digits than its factorization.

19749051840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3675 (or 3665 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 48.

The spelling of 19749051840 in words is "nineteen billion, seven hundred forty-nine million, fifty-one thousand, eight hundred forty".