1997806564 has 36 divisors (see below), whose sum is σ = 3870654844. Its totient is φ = 896263488.

The previous prime is 1997806537. The next prime is 1997806579. The reversal of 1997806564 is 4656087991.

It can be written as a sum of positive squares in 2 ways, for example, as 1063281664 + 934524900 = 32608^2 + 30570^2 .

It is a super-2 number, since 2×1997806564² = 7982462134322972192, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1960047 + ... + 1961065.

Almost surely, 2^1997806564 is an apocalyptic number.

It is an amenable number.

1997806564 is a deficient number, since it is larger than the sum of its proper divisors (1872848280).

1997806564 is a wasteful number, since it uses less digits than its factorization.

1997806564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2092 (or 1071 counting only the distinct ones).

The product of its (nonzero) digits is 3265920, while the sum is 55.

The square root of 1997806564 is about 44696.8294625021. The cubic root of 1997806564 is about 1259.4602887141.

The spelling of 1997806564 in words is "one billion, nine hundred ninety-seven million, eight hundred six thousand, five hundred sixty-four".