255221661 has 8 divisors (see below), whose sum is σ = 358205920. Its totient is φ = 161192592.

The previous prime is 255221657. The next prime is 255221677. The reversal of 255221661 is 166122552.

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

It is not a de Polignac number, because 255221661 - 2² = 255221657 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 (255221611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2238730 + ... + 2238843.

It is an arithmetic number, because the mean of its divisors is an integer number (44775740).

Almost surely, 2^255221661 is an apocalyptic number.

It is an amenable number.

255221661 is a deficient number, since it is larger than the sum of its proper divisors (102984259).

255221661 is a wasteful number, since it uses less digits than its factorization.

255221661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4477595.

The product of its digits is 7200, while the sum is 30.

The square root of 255221661 is about 15975.6583901885. The cubic root of 255221661 is about 634.3162591019.

The spelling of 255221661 in words is "two hundred fifty-five million, two hundred twenty-one thousand, six hundred sixty-one".