12210781538 has 6 divisors (see below), whose sum is σ = 18316406721. Its totient is φ = 6105312632.

The previous prime is 12210781529. The next prime is 12210781601. The reversal of 12210781538 is 83518701221.

It can be written as a sum of positive squares in 2 ways, for example, as 11550445729 + 660335809 = 107473^2 + 25697^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=78137.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 117206 + ... + 195342.

Almost surely, 2^12210781538 is an apocalyptic number.

12210781538 is a deficient number, since it is larger than the sum of its proper divisors (6105625183).

12210781538 is an frugal number, since it uses more digits than its factorization.

12210781538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156276 (or 78139 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 38.

The spelling of 12210781538 in words is "twelve billion, two hundred ten million, seven hundred eighty-one thousand, five hundred thirty-eight".