217406442 has 64 divisors (see below), whose sum is σ = 498161664. Its totient is φ = 62610240.

The previous prime is 217406401. The next prime is 217406447. The reversal of 217406442 is 244604712.

It is a super-2 number, since 2×217406442² = 94531122046198728, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (217406447) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 298683 + ... + 299409.

It is an arithmetic number, because the mean of its divisors is an integer number (7783776).

Almost surely, 2^217406442 is an apocalyptic number.

217406442 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 217406442, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (249080832).

217406442 is an abundant number, since it is smaller than the sum of its proper divisors (280755222).

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

217406442 is a wasteful number, since it uses less digits than its factorization.

217406442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 963.

The product of its (nonzero) digits is 10752, while the sum is 30.

The square root of 217406442 is about 14744.7089493147. The cubic root of 217406442 is about 601.2994448181.

It can be divided in two parts, 21740 and 6442, that added together give a palindrome (28182).

The spelling of 217406442 in words is "two hundred seventeen million, four hundred six thousand, four hundred forty-two".