217049903890 has 8 divisors (see below), whose sum is σ = 390689827020. Its totient is φ = 86819961552.

The previous prime is 217049903879. The next prime is 217049903899. The reversal of 217049903890 is 98309940712.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 199927919689 + 17121984201 = 447133^2 + 130851^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×217049903890² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (217049903899) 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, 10852495185 + ... + 10852495204.

Almost surely, 2^217049903890 is an apocalyptic number.

217049903890 is a deficient number, since it is larger than the sum of its proper divisors (173639923130).

217049903890 is a wasteful number, since it uses less digits than its factorization.

217049903890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21704990396.

The product of its (nonzero) digits is 979776, while the sum is 52.

The spelling of 217049903890 in words is "two hundred seventeen billion, forty-nine million, nine hundred three thousand, eight hundred ninety".