216918673920 has 560 divisors, whose sum is σ = 839865510792. Its totient is φ = 53389393920.

The previous prime is 216918673913. The next prime is 216918673967. The reversal of 216918673920 is 29376819612.

It can be written as a sum of positive squares in 4 ways, for example, as 152174889216 + 64743784704 = 390096^2 + 254448^2 .

It is a super-2 number, since 2×216918673920² (a number of 23 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 24256650 + ... + 24265590.

Almost surely, 2^216918673920 is an apocalyptic number.

216918673920 is a gapful number since it is divisible by the number (20) 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 216918673920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (419932755396).

216918673920 is an abundant number, since it is smaller than the sum of its proper divisors (622946836872).

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

216918673920 is an frugal number, since it uses more digits than its factorization.

216918673920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8995 (or 8964 counting only the distinct ones).

The product of its (nonzero) digits is 1959552, while the sum is 54.

The spelling of 216918673920 in words is "two hundred sixteen billion, nine hundred eighteen million, six hundred seventy-three thousand, nine hundred twenty".