1997918208 has 312 divisors, whose sum is σ = 6797874720. Its totient is φ = 557383680.

The previous prime is 1997918201. The next prime is 1997918227. The reversal of 1997918208 is 8028197991.

It is a tau number, because it is divible by the number of its divisors (312).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1997918201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5271363 + ... + 5271741.

It is an arithmetic number, because the mean of its divisors is an integer number (21788060).

Almost surely, 2^1997918208 is an apocalyptic number.

1997918208 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 1997918208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3398937360).

1997918208 is an abundant number, since it is smaller than the sum of its proper divisors (4799956512).

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

1997918208 is a wasteful number, since it uses less digits than its factorization.

1997918208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433 (or 408 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 54.

The square root of 1997918208 is about 44698.0783479559. The cubic root of 1997918208 is about 1259.4837492045.

The spelling of 1997918208 in words is "one billion, nine hundred ninety-seven million, nine hundred eighteen thousand, two hundred eight".