1997936640 has 576 divisors, whose sum is σ = 8381318400. Its totient is φ = 429981696.

The previous prime is 1997936573. The next prime is 1997936671. The reversal of 1997936640 is 466397991.

It is a tau number, because it is divible by the number of its divisors (576).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 12257199 + ... + 12257361.

It is an arithmetic number, because the mean of its divisors is an integer number (14550900).

Almost surely, 2^1997936640 is an apocalyptic number.

1997936640 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 1997936640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4190659200).

1997936640 is an abundant number, since it is smaller than the sum of its proper divisors (6383381760).

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

1997936640 is a wasteful number, since it uses less digits than its factorization.

1997936640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222 (or 199 counting only the distinct ones).

The product of its (nonzero) digits is 2204496, while the sum is 54.

The square root of 1997936640 is about 44698.2845308408. The cubic root of 1997936640 is about 1259.4876223583.

The spelling of 1997936640 in words is "one billion, nine hundred ninety-seven million, nine hundred thirty-six thousand, six hundred forty".