4256021 has 16 divisors (see below), whose sum is σ = 5480448. Its totient is φ = 3207600.

The previous prime is 4256009. The next prime is 4256029. The reversal of 4256021 is 1206524.

It is a happy number.

It is not a de Polignac number, because 4256021 - 2²² = 61717 is a prime.

It is a super-2 number, since 2×4256021² = 36227429504882, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 4255984 and 4256002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4256029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1496 + ... + 3278.

It is an arithmetic number, because the mean of its divisors is an integer number (342528).

Almost surely, 2^4256021 is an apocalyptic number.

It is an amenable number.

4256021 is a deficient number, since it is larger than the sum of its proper divisors (1224427).

4256021 is a wasteful number, since it uses less digits than its factorization.

4256021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1832.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 4256021 is about 2063.0126029668. The cubic root of 4256021 is about 162.0570469212.

It can be divided in two parts, 425 and 6021, that added together give a palindrome (6446).

The spelling of 4256021 in words is "four million, two hundred fifty-six thousand, twenty-one".