217428738 has 8 divisors (see below), whose sum is σ = 434857488. Its totient is φ = 72476244.

The previous prime is 217428733. The next prime is 217428749. The reversal of 217428738 is 837824712.

217428738 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

217428738 is an admirable number.

It is a super-2 number, since 2×217428738² = 94550512216545288, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 217428738.

It is not an unprimeable number, because it can be changed into a prime (217428733) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18119056 + ... + 18119067.

It is an arithmetic number, because the mean of its divisors is an integer number (54357186).

Almost surely, 2^217428738 is an apocalyptic number.

217428738 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

217428738 is a wasteful number, since it uses less digits than its factorization.

217428738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36238128.

The product of its digits is 150528, while the sum is 42.

The square root of 217428738 is about 14745.4649977544. The cubic root of 217428738 is about 601.3199994285.

The spelling of 217428738 in words is "two hundred seventeen million, four hundred twenty-eight thousand, seven hundred thirty-eight".