1990659887 has 16 divisors (see below), whose sum is σ = 2120152320. Its totient is φ = 1863763200.

The previous prime is 1990659883. The next prime is 1990659893. The reversal of 1990659887 is 7889560991.

It is not a de Polignac number, because 1990659887 - 2² = 1990659883 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1990659883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 653087 + ... + 656127.

It is an arithmetic number, because the mean of its divisors is an integer number (132509520).

Almost surely, 2^1990659887 is an apocalyptic number.

1990659887 is a deficient number, since it is larger than the sum of its proper divisors (129492433).

1990659887 is a wasteful number, since it uses less digits than its factorization.

1990659887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3454.

The product of its (nonzero) digits is 9797760, while the sum is 62.

The square root of 1990659887 is about 44616.8117081443. The cubic root of 1990659887 is about 1257.9566879908.

The spelling of 1990659887 in words is "one billion, nine hundred ninety million, six hundred fifty-nine thousand, eight hundred eighty-seven".