209961478783 has 4 divisors (see below), whose sum is σ = 239955975760. Its totient is φ = 179966981808.

The previous prime is 209961478763. The next prime is 209961478801. The reversal of 209961478783 is 387874169902.

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

It is a cyclic number.

It is not a de Polignac number, because 209961478783 - 2²⁵ = 209927924351 is a prime.

It is a super-3 number, since 3×209961478783³ (a number of 35 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209961478733) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14997248478 + ... + 14997248491.

It is an arithmetic number, because the mean of its divisors is an integer number (59988993940).

Almost surely, 2^209961478783 is an apocalyptic number.

209961478783 is a deficient number, since it is larger than the sum of its proper divisors (29994496977).

209961478783 is an equidigital number, since it uses as much as digits as its factorization.

209961478783 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29994496976.

The product of its (nonzero) digits is 36578304, while the sum is 64.

The spelling of 209961478783 in words is "two hundred nine billion, nine hundred sixty-one million, four hundred seventy-eight thousand, seven hundred eighty-three".