217000051 has 4 divisors (see below), whose sum is σ = 217224504. Its totient is φ = 216775600.

The previous prime is 217000039. The next prime is 217000061. The reversal of 217000051 is 150000712.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217000051 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 216999989 and 217000034.

It is not an unprimeable number, because it can be changed into a prime (217000001) 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, 110770 + ... + 112711.

It is an arithmetic number, because the mean of its divisors is an integer number (54306126).

Almost surely, 2^217000051 is an apocalyptic number.

217000051 is a deficient number, since it is larger than the sum of its proper divisors (224453).

217000051 is an equidigital number, since it uses as much as digits as its factorization.

217000051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224452.

The product of its (nonzero) digits is 70, while the sum is 16.

The square root of 217000051 is about 14730.9215937089. The cubic root of 217000051 is about 600.9245477688.

Adding to 217000051 its reverse (150000712), we get a palindrome (367000763).

The spelling of 217000051 in words is "two hundred seventeen million, fifty-one", and thus it is an aban number.