6451639 has 4 divisors (see below), whose sum is σ = 6467040. Its totient is φ = 6436240.

The previous prime is 6451633. The next prime is 6451649. The reversal of 6451639 is 9361546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9361546 = 2 ⋅4680773.

It is a cyclic number.

It is not a de Polignac number, because 6451639 - 2¹³ = 6443447 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6451633) 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, 7054 + ... + 7915.

It is an arithmetic number, because the mean of its divisors is an integer number (1616760).

Almost surely, 2^6451639 is an apocalyptic number.

6451639 is a deficient number, since it is larger than the sum of its proper divisors (15401).

6451639 is a wasteful number, since it uses less digits than its factorization.

6451639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15400.

The product of its digits is 19440, while the sum is 34.

The square root of 6451639 is about 2540.0076771538. The cubic root of 6451639 is about 186.1615642493.

The spelling of 6451639 in words is "six million, four hundred fifty-one thousand, six hundred thirty-nine".