7640639 has 4 divisors (see below), whose sum is σ = 7784856. Its totient is φ = 7496424.

The previous prime is 7640621. The next prime is 7640681. The reversal of 7640639 is 9360467.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9360467 = 107 ⋅87481.

It is a cyclic number.

It is not a de Polignac number, because 7640639 - 2¹⁶ = 7575103 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 7640599 and 7640608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7610639) 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, 72029 + ... + 72134.

It is an arithmetic number, because the mean of its divisors is an integer number (1946214).

Almost surely, 2^7640639 is an apocalyptic number.

7640639 is a deficient number, since it is larger than the sum of its proper divisors (144217).

7640639 is a wasteful number, since it uses less digits than its factorization.

7640639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144216.

The product of its (nonzero) digits is 27216, while the sum is 35.

The square root of 7640639 is about 2764.1705808434. The cubic root of 7640639 is about 196.9593309333.

The spelling of 7640639 in words is "seven million, six hundred forty thousand, six hundred thirty-nine".