218393733978 has 448 divisors, whose sum is σ = 618036832512. Its totient is φ = 56435097600.

The previous prime is 218393733959. The next prime is 218393733983. The reversal of 218393733978 is 879337393812.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 223 ways as a sum of consecutive naturals, for example, 544622578 + ... + 544622978.

Almost surely, 2^218393733978 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 218393733978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (309018416256).

218393733978 is an abundant number, since it is smaller than the sum of its proper divisors (399643098534).

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

218393733978 is a wasteful number, since it uses less digits than its factorization.

218393733978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 561 (or 546 counting only the distinct ones).

The product of its digits is 41150592, while the sum is 63.

The spelling of 218393733978 in words is "two hundred eighteen billion, three hundred ninety-three million, seven hundred thirty-three thousand, nine hundred seventy-eight".