2639981 has 8 divisors (see below), whose sum is σ = 2830464. Its totient is φ = 2453440.

The previous prime is 2639971. The next prime is 2639999. The reversal of 2639981 is 1899362.

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

It is not a de Polignac number, because 2639981 - 2¹⁴ = 2623597 is a prime.

It is a super-2 number, since 2×2639981² = 13938999360722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2639911) 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, 476 + ... + 2346.

It is an arithmetic number, because the mean of its divisors is an integer number (353808).

2^2639981 is an apocalyptic number.

It is an amenable number.

2639981 is a deficient number, since it is larger than the sum of its proper divisors (190483).

2639981 is a wasteful number, since it uses less digits than its factorization.

2639981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1971.

The product of its digits is 23328, while the sum is 38.

The square root of 2639981 is about 1624.8018340709. The cubic root of 2639981 is about 138.2081330387.

The spelling of 2639981 in words is "two million, six hundred thirty-nine thousand, nine hundred eighty-one".