385721904217 has 4 divisors (see below), whose sum is σ = 415392819940. Its totient is φ = 356050988496.

The previous prime is 385721904157. The next prime is 385721904229. The reversal of 385721904217 is 712409127583.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 712409127583 = 83 ⋅8583242501.

It can be written as a sum of positive squares in 2 ways, for example, as 228851251456 + 156870652761 = 478384^2 + 396069^2 .

It is a cyclic number.

It is not a de Polignac number, because 385721904217 - 2²³ = 385713515609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (385721904257) 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, 14835457842 + ... + 14835457867.

It is an arithmetic number, because the mean of its divisors is an integer number (103848204985).

Almost surely, 2^385721904217 is an apocalyptic number.

It is an amenable number.

385721904217 is a deficient number, since it is larger than the sum of its proper divisors (29670915723).

385721904217 is a wasteful number, since it uses less digits than its factorization.

385721904217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29670915722.

The product of its (nonzero) digits is 846720, while the sum is 49.

The spelling of 385721904217 in words is "three hundred eighty-five billion, seven hundred twenty-one million, nine hundred four thousand, two hundred seventeen".