256420551 has 8 divisors (see below), whose sum is σ = 342284800. Its totient is φ = 170751672.

The previous prime is 256420513. The next prime is 256420553. The reversal of 256420551 is 155024652.

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

It is not a de Polignac number, because 256420551 - 2⁶ = 256420487 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 (256420553) 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, 45751 + ... + 51048.

It is an arithmetic number, because the mean of its divisors is an integer number (42785600).

Almost surely, 2^256420551 is an apocalyptic number.

256420551 is a deficient number, since it is larger than the sum of its proper divisors (85864249).

256420551 is an equidigital number, since it uses as much as digits as its factorization.

256420551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97685.

The product of its (nonzero) digits is 12000, while the sum is 30.

The square root of 256420551 is about 16013.1368257440. The cubic root of 256420551 is about 635.3079300944.

The spelling of 256420551 in words is "two hundred fifty-six million, four hundred twenty thousand, five hundred fifty-one".