221907 has 8 divisors (see below), whose sum is σ = 338176. Its totient is φ = 126792.

The previous prime is 221891. The next prime is 221909. The reversal of 221907 is 709122.

It is a happy number.

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

It is not a de Polignac number, because 221907 - 2⁴ = 221891 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 10567 = 221907 / (2 + 2 + 1 + 9 + 0 + 7).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221909) 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, 5263 + ... + 5304.

It is an arithmetic number, because the mean of its divisors is an integer number (42272).

2²²¹⁹⁰⁷ is an apocalyptic number.

221907 is a deficient number, since it is larger than the sum of its proper divisors (116269).

221907 is a wasteful number, since it uses less digits than its factorization.

221907 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10577.

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 221907 is about 471.0700584839. The cubic root of 221907 is about 60.5420330356.

It can be divided in two parts, 221 and 907, that added together give a triangular number (1128 = T₄₇).

The spelling of 221907 in words is "two hundred twenty-one thousand, nine hundred seven".