217428920 has 16 divisors (see below), whose sum is σ = 489215160. Its totient is φ = 86971552.

The previous prime is 217428917. The next prime is 217428923. The reversal of 217428920 is 29824712.

It is an interprime number because it is at equal distance from previous prime (217428917) and next prime (217428923).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217428923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2717822 + ... + 2717901.

Almost surely, 2^217428920 is an apocalyptic number.

217428920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

217428920 is an abundant number, since it is smaller than the sum of its proper divisors (271786240).

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

217428920 is a wasteful number, since it uses less digits than its factorization.

217428920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5435734 (or 5435730 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 217428920 is about 14745.4711691421. The cubic root of 217428920 is about 601.3201672079.

The spelling of 217428920 in words is "two hundred seventeen million, four hundred twenty-eight thousand, nine hundred twenty".