217642 has 4 divisors (see below), whose sum is σ = 326466. Its totient is φ = 108820.

The previous prime is 217619. The next prime is 217643. The reversal of 217642 is 246712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 177241 + 40401 = 421^2 + 201^2 .

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (217643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54409 + ... + 54412.

2²¹⁷⁶⁴² is an apocalyptic number.

217642 is a deficient number, since it is larger than the sum of its proper divisors (108824).

217642 is a wasteful number, since it uses less digits than its factorization.

217642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108823.

The product of its digits is 672, while the sum is 22.

The square root of 217642 is about 466.5211677941. The cubic root of 217642 is about 60.1516534015.

The spelling of 217642 in words is "two hundred seventeen thousand, six hundred forty-two".