1997665964 has 48 divisors (see below), whose sum is σ = 4198833408. Its totient is φ = 813613248.

The previous prime is 1997665963. The next prime is 1997665981. The reversal of 1997665964 is 4695667991.

It is a junction number, because it is equal to n+sod(n) for n = 1997665897 and 1997665906.

It is not an unprimeable number, because it can be changed into a prime (1997665961) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22127 + ... + 66969.

It is an arithmetic number, because the mean of its divisors is an integer number (87475696).

Almost surely, 2^1997665964 is an apocalyptic number.

1997665964 is a gapful number since it is divisible by the number (14) 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 1997665964, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2099416704).

1997665964 is an abundant number, since it is smaller than the sum of its proper divisors (2201167444).

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

1997665964 is a wasteful number, since it uses less digits than its factorization.

1997665964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44934 (or 44932 counting only the distinct ones).

The product of its digits is 22044960, while the sum is 62.

The square root of 1997665964 is about 44695.2566163346. The cubic root of 1997665964 is about 1259.4307422648.

The spelling of 1997665964 in words is "one billion, nine hundred ninety-seven million, six hundred sixty-five thousand, nine hundred sixty-four".