217787020973 has 4 divisors (see below), whose sum is σ = 217799824188. Its totient is φ = 217774217760.

The previous prime is 217787020951. The next prime is 217787021003. The reversal of 217787020973 is 379020787712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 129091459849 + 88695561124 = 359293^2 + 297818^2 .

It is a cyclic number.

It is not a de Polignac number, because 217787020973 - 2¹² = 217787016877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217787020943) 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, 6376058 + ... + 6410123.

It is an arithmetic number, because the mean of its divisors is an integer number (54449956047).

Almost surely, 2^217787020973 is an apocalyptic number.

It is an amenable number.

217787020973 is a deficient number, since it is larger than the sum of its proper divisors (12803215).

217787020973 is a wasteful number, since it uses less digits than its factorization.

217787020973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12803214.

The product of its (nonzero) digits is 2074464, while the sum is 53.

The spelling of 217787020973 in words is "two hundred seventeen billion, seven hundred eighty-seven million, twenty thousand, nine hundred seventy-three".