217406742 has 64 divisors (see below), whose sum is σ = 511847424. Its totient is φ = 60278400.

The previous prime is 217406731. The next prime is 217406789. The reversal of 217406742 is 247604712.

217406742 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 224343 + ... + 225309.

It is an arithmetic number, because the mean of its divisors is an integer number (7997616).

Almost surely, 2^217406742 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 217406742, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (255923712).

217406742 is an abundant number, since it is smaller than the sum of its proper divisors (294440682).

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

217406742 is a wasteful number, since it uses less digits than its factorization.

217406742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1133.

The product of its (nonzero) digits is 18816, while the sum is 33.

The square root of 217406742 is about 14744.7191224519. The cubic root of 217406742 is about 601.2997213964.

It can be divided in two parts, 21740 and 6742, that added together give a palindrome (28482).

The spelling of 217406742 in words is "two hundred seventeen million, four hundred six thousand, seven hundred forty-two".