217916901 has 6 divisors (see below), whose sum is σ = 314768870. Its totient is φ = 145277928.

The previous prime is 217916857. The next prime is 217916903. The reversal of 217916901 is 109619712.

It can be written as a sum of positive squares in only one way, i.e., 217592001 + 324900 = 14751^2 + 570^2 .

It is not a de Polignac number, because 217916901 - 2⁷ = 217916773 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217916903) 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 5 ways as a sum of consecutive naturals, for example, 12106486 + ... + 12106503.

Almost surely, 2^217916901 is an apocalyptic number.

It is an amenable number.

217916901 is a deficient number, since it is larger than the sum of its proper divisors (96851969).

217916901 is a wasteful number, since it uses less digits than its factorization.

217916901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24212995 (or 24212992 counting only the distinct ones).

The product of its (nonzero) digits is 6804, while the sum is 36.

The square root of 217916901 is about 14762.0087047800. The cubic root of 217916901 is about 601.7696835684.

The spelling of 217916901 in words is "two hundred seventeen million, nine hundred sixteen thousand, nine hundred one".