256532021 has 8 divisors (see below), whose sum is σ = 260407224. Its totient is φ = 252683200.

The previous prime is 256532009. The next prime is 256532069. The reversal of 256532021 is 120235652.

It can be written as a sum of positive squares in 4 ways, for example, as 194909521 + 61622500 = 13961^2 + 7850^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256532021 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 (256532321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13451 + ... + 26343.

It is an arithmetic number, because the mean of its divisors is an integer number (32550903).

Almost surely, 2^256532021 is an apocalyptic number.

It is an amenable number.

256532021 is a deficient number, since it is larger than the sum of its proper divisors (3875203).

256532021 is a wasteful number, since it uses less digits than its factorization.

256532021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13191.

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 256532021 is about 16016.6170273251. The cubic root of 256532021 is about 635.3999761691.

Adding to 256532021 its reverse (120235652), we get a palindrome (376767673).

The spelling of 256532021 in words is "two hundred fifty-six million, five hundred thirty-two thousand, twenty-one".