7681639 has 4 divisors (see below), whose sum is σ = 8779024. Its totient is φ = 6584256.

The previous prime is 7681631. The next prime is 7681651. The reversal of 7681639 is 9361867.

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

It is not a de Polignac number, because 7681639 - 2³ = 7681631 is a prime.

It is a Duffinian number.

7681639 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7681631) 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, 548682 + ... + 548695.

It is an arithmetic number, because the mean of its divisors is an integer number (2194756).

Almost surely, 2^7681639 is an apocalyptic number.

7681639 is a deficient number, since it is larger than the sum of its proper divisors (1097385).

7681639 is a wasteful number, since it uses less digits than its factorization.

7681639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1097384.

The product of its digits is 54432, while the sum is 40.

The square root of 7681639 is about 2771.5769879258. The cubic root of 7681639 is about 197.3110000925.

The spelling of 7681639 in words is "seven million, six hundred eighty-one thousand, six hundred thirty-nine".