19778091840 has 224 divisors, whose sum is σ = 75140271360. Its totient is φ = 4868425728.

The previous prime is 19778091797. The next prime is 19778091841. The reversal of 19778091840 is 4819087791.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19778091841) 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, 24277 + ... + 200363.

It is an arithmetic number, because the mean of its divisors is an integer number (335447640).

Almost surely, 2^19778091840 is an apocalyptic number.

19778091840 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 19778091840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37570135680).

19778091840 is an abundant number, since it is smaller than the sum of its proper divisors (55362179520).

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

19778091840 is a wasteful number, since it uses less digits than its factorization.

19778091840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176126 (or 176110 counting only the distinct ones).

The product of its (nonzero) digits is 1016064, while the sum is 54.

It can be divided in two parts, 1977809 and 1840, that added together give a square (1979649 = 1407²).

The spelling of 19778091840 in words is "nineteen billion, seven hundred seventy-eight million, ninety-one thousand, eight hundred forty".