2639987 has 8 divisors (see below), whose sum is σ = 3098976. Its totient is φ = 2201472.

The previous prime is 2639971. The next prime is 2639999. The reversal of 2639987 is 7899362.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2639987 - 2⁴ = 2639971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2639927) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4838 + ... + 5355.

It is an arithmetic number, because the mean of its divisors is an integer number (387372).

2^2639987 is an apocalyptic number.

2639987 is a deficient number, since it is larger than the sum of its proper divisors (458989).

2639987 is a wasteful number, since it uses less digits than its factorization.

2639987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10237.

The product of its digits is 163296, while the sum is 44.

The square root of 2639987 is about 1624.8036804488. The cubic root of 2639987 is about 138.2082377425.

The spelling of 2639987 in words is "two million, six hundred thirty-nine thousand, nine hundred eighty-seven".