18419991408 has 720 divisors, whose sum is σ = 70363353600. Its totient is φ = 4585351680.

The previous prime is 18419991383. The next prime is 18419991413. The reversal of 18419991408 is 80419991481.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 67970313 + ... + 67970583.

It is an arithmetic number, because the mean of its divisors is an integer number (97726880).

Almost surely, 2^18419991408 is an apocalyptic number.

18419991408 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 18419991408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35181676800).

18419991408 is an abundant number, since it is smaller than the sum of its proper divisors (51943362192).

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

18419991408 is a wasteful number, since it uses less digits than its factorization.

18419991408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 347 (or 315 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 54.

The spelling of 18419991408 in words is "eighteen billion, four hundred nineteen million, nine hundred ninety-one thousand, four hundred eight".