4256639 has 2 divisors, whose sum is σ = 4256640. Its totient is φ = 4256638.

The previous prime is 4256617. The next prime is 4256653. The reversal of 4256639 is 9366524.

4256639 is nontrivially palindromic in base 9.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 4256639 - 2⁸ = 4256383 is a prime.

It is a d-powerful number, because it can be written as 4¹¹ + 2³ + 5⁵ + 6² + 6² + 3¹⁰ + 9² .

It is a junction number, because it is equal to n+sod(n) for n = 4256599 and 4256608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4256669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2128319 + 2128320.

It is an arithmetic number, because the mean of its divisors is an integer number (2128320).

Almost surely, 2^4256639 is an apocalyptic number.

4256639 is a deficient number, since it is larger than the sum of its proper divisors (1).

4256639 is an equidigital number, since it uses as much as digits as its factorization.

4256639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 35.

The square root of 4256639 is about 2063.1623784860. The cubic root of 4256639 is about 162.0648904295.

The spelling of 4256639 in words is "four million, two hundred fifty-six thousand, six hundred thirty-nine".