1990660587 has 4 divisors (see below), whose sum is σ = 2654214120. Its totient is φ = 1327107056.

The previous prime is 1990660537. The next prime is 1990660591. The reversal of 1990660587 is 7850660991.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1990660587 - 2⁶ = 1990660523 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1990660537) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 331776762 + ... + 331776767.

It is an arithmetic number, because the mean of its divisors is an integer number (663553530).

Almost surely, 2^1990660587 is an apocalyptic number.

1990660587 is a deficient number, since it is larger than the sum of its proper divisors (663553533).

1990660587 is an equidigital number, since it uses as much as digits as its factorization.

1990660587 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 663553532.

The product of its (nonzero) digits is 816480, while the sum is 51.

The square root of 1990660587 is about 44616.8195527202. The cubic root of 1990660587 is about 1257.9568354410.

The spelling of 1990660587 in words is "one billion, nine hundred ninety million, six hundred sixty thousand, five hundred eighty-seven".