217428645 has 16 divisors (see below), whose sum is σ = 397584000. Its totient is φ = 99395904.

The previous prime is 217428587. The next prime is 217428661. The reversal of 217428645 is 546824712.

It is not a de Polignac number, because 217428645 - 2¹¹ = 217426597 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1035270 + ... + 1035479.

It is an arithmetic number, because the mean of its divisors is an integer number (24849000).

Almost surely, 2^217428645 is an apocalyptic number.

It is an amenable number.

217428645 is a deficient number, since it is larger than the sum of its proper divisors (180155355).

217428645 is a wasteful number, since it uses less digits than its factorization.

217428645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2070764.

The product of its digits is 107520, while the sum is 39.

The square root of 217428645 is about 14745.4618442421. The cubic root of 217428645 is about 601.3199136950.

The spelling of 217428645 in words is "two hundred seventeen million, four hundred twenty-eight thousand, six hundred forty-five".