209155339081 has 4 divisors (see below), whose sum is σ = 225244211332. Its totient is φ = 193066466832.

The previous prime is 209155339069. The next prime is 209155339163. The reversal of 209155339081 is 180933551902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 180933551902 = 2 ⋅90466775951.

It can be written as a sum of positive squares in 2 ways, for example, as 32154227856 + 177001111225 = 179316^2 + 420715^2 .

It is a cyclic number.

It is not a de Polignac number, because 209155339081 - 2¹³ = 209155330889 is a prime.

It is a super-2 number, since 2×209155339081² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (209155339031) 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, 8044436106 + ... + 8044436131.

It is an arithmetic number, because the mean of its divisors is an integer number (56311052833).

Almost surely, 2^209155339081 is an apocalyptic number.

It is an amenable number.

209155339081 is a deficient number, since it is larger than the sum of its proper divisors (16088872251).

209155339081 is a wasteful number, since it uses less digits than its factorization.

209155339081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16088872250.

The product of its (nonzero) digits is 291600, while the sum is 46.

The spelling of 209155339081 in words is "two hundred nine billion, one hundred fifty-five million, three hundred thirty-nine thousand, eighty-one".