256573421 has 4 divisors (see below), whose sum is σ = 276309852. Its totient is φ = 236836992.

The previous prime is 256573403. The next prime is 256573451. The reversal of 256573421 is 124375652.

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

It can be written as a sum of positive squares in 2 ways, for example, as 137217796 + 119355625 = 11714^2 + 10925^2 .

It is a cyclic number.

It is not a de Polignac number, because 256573421 - 2⁶ = 256573357 is a prime.

It is a super-4 number, since 4×256573421⁴ (a number of 35 digits) contains 4444 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256573451) 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, 9868196 + ... + 9868221.

It is an arithmetic number, because the mean of its divisors is an integer number (69077463).

Almost surely, 2^256573421 is an apocalyptic number.

It is an amenable number.

256573421 is a deficient number, since it is larger than the sum of its proper divisors (19736431).

256573421 is a wasteful number, since it uses less digits than its factorization.

256573421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19736430.

The product of its digits is 50400, while the sum is 35.

The square root of 256573421 is about 16017.9093829376. The cubic root of 256573421 is about 635.4341553253.

The spelling of 256573421 in words is "two hundred fifty-six million, five hundred seventy-three thousand, four hundred twenty-one".