221256361 has 4 divisors (see below), whose sum is σ = 221342292. Its totient is φ = 221170432.

The previous prime is 221256319. The next prime is 221256379. The reversal of 221256361 is 163652122.

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 130416400 + 90839961 = 11420^2 + 9531^2 .

It is a cyclic number.

It is not a de Polignac number, because 221256361 - 2⁹ = 221255849 is a prime.

It is a super-3 number, since 3×221256361³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221256461) 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, 38980 + ... + 44293.

It is an arithmetic number, because the mean of its divisors is an integer number (55335573).

Almost surely, 2^221256361 is an apocalyptic number.

It is an amenable number.

221256361 is a deficient number, since it is larger than the sum of its proper divisors (85931).

221256361 is an equidigital number, since it uses as much as digits as its factorization.

221256361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85930.

The product of its digits is 4320, while the sum is 28.

The square root of 221256361 is about 14874.6886017826. The cubic root of 221256361 is about 604.8280466628.

The spelling of 221256361 in words is "two hundred twenty-one million, two hundred fifty-six thousand, three hundred sixty-one".