215442 has 12 divisors (see below), whose sum is σ = 466830. Its totient is φ = 71808.

The previous prime is 215417. The next prime is 215443. The reversal of 215442 is 244512.

It can be written as a sum of positive squares in only one way, i.e., 210681 + 4761 = 459^2 + 69^2 .

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 11969 = 215442 / (2 + 1 + 5 + 4 + 4 + 2).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215443) by changing a digit.

215442 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5967 + ... + 6002.

2²¹⁵⁴⁴² is an apocalyptic number.

215442 is an abundant number, since it is smaller than the sum of its proper divisors (251388).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

215442 is a wasteful number, since it uses less digits than its factorization.

215442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11977 (or 11974 counting only the distinct ones).

The product of its digits is 320, while the sum is 18.

The square root of 215442 is about 464.1573009229. The cubic root of 215442 is about 59.9482887786.

Adding to 215442 its reverse (244512), we get a palindrome (459954).

The spelling of 215442 in words is "two hundred fifteen thousand, four hundred forty-two".