221407421 has 8 divisors (see below), whose sum is σ = 227022264. Its totient is φ = 215802880.

The previous prime is 221407411. The next prime is 221407441. The reversal of 221407421 is 124704122.

It can be written as a sum of positive squares in 4 ways, for example, as 290521 + 221116900 = 539^2 + 14870^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 221407421 - 2⁶ = 221407357 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221407411) 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, 59405 + ... + 63021.

It is an arithmetic number, because the mean of its divisors is an integer number (28377783).

Almost surely, 2^221407421 is an apocalyptic number.

It is an amenable number.

221407421 is a deficient number, since it is larger than the sum of its proper divisors (5614843).

221407421 is a wasteful number, since it uses less digits than its factorization.

221407421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5151.

The product of its (nonzero) digits is 896, while the sum is 23.

The square root of 221407421 is about 14879.7654887434. The cubic root of 221407421 is about 604.9656615986.

The spelling of 221407421 in words is "two hundred twenty-one million, four hundred seven thousand, four hundred twenty-one".