209981315664 has 60 divisors (see below), whose sum is σ = 601989134292. Its totient is φ = 68286604800.

The previous prime is 209981315657. The next prime is 209981315681. The reversal of 209981315664 is 466513189902.

It can be written as a sum of positive squares in 2 ways, for example, as 67595840064 + 142385475600 = 259992^2 + 377340^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 209981315664.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17777067 + ... + 17788874.

Almost surely, 2^209981315664 is an apocalyptic number.

209981315664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

209981315664 is an abundant number, since it is smaller than the sum of its proper divisors (392007818628).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

209981315664 is a wasteful number, since it uses less digits than its factorization.

209981315664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35565996 (or 35565987 counting only the distinct ones).

The product of its (nonzero) digits is 2799360, while the sum is 54.

The spelling of 209981315664 in words is "two hundred nine billion, nine hundred eighty-one million, three hundred fifteen thousand, six hundred sixty-four".