256721034 has 32 divisors (see below), whose sum is σ = 524180160. Its totient is φ = 83802752.

The previous prime is 256720991. The next prime is 256721039. The reversal of 256721034 is 430127652.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 256720992 and 256721010.

It is not an unprimeable number, because it can be changed into a prime (256721039) 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, 54892 + ... + 59384.

It is an arithmetic number, because the mean of its divisors is an integer number (16380630).

Almost surely, 2^256721034 is an apocalyptic number.

256721034 is an abundant number, since it is smaller than the sum of its proper divisors (267459126).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

256721034 is a wasteful number, since it uses less digits than its factorization.

256721034 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4694.

The product of its (nonzero) digits is 10080, while the sum is 30.

The square root of 256721034 is about 16022.5164690195. The cubic root of 256721034 is about 635.5559922627. Note that the first 3 decimals are identical.

Adding to 256721034 its reverse (430127652), we get a palindrome (686848686).

The spelling of 256721034 in words is "two hundred fifty-six million, seven hundred twenty-one thousand, thirty-four".