1669987 has 4 divisors (see below), whose sum is σ = 1821816. Its totient is φ = 1518160.

The previous prime is 1669979. The next prime is 1669999. The reversal of 1669987 is 7899661.

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 1669987 - 2³ = 1669979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1669937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75898 + ... + 75919.

It is an arithmetic number, because the mean of its divisors is an integer number (455454).

2^1669987 is an apocalyptic number.

1669987 is a deficient number, since it is larger than the sum of its proper divisors (151829).

1669987 is a wasteful number, since it uses less digits than its factorization.

1669987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151828.

The product of its digits is 163296, while the sum is 46.

The square root of 1669987 is about 1292.2797684712. The cubic root of 1669987 is about 118.6417917323.

It can be divided in two parts, 166 and 9987, that added together give a triangular number (10153 = T₁₄₂).

The spelling of 1669987 in words is "one million, six hundred sixty-nine thousand, nine hundred eighty-seven".