181367812129 has 27 divisors (see below), whose sum is σ = 213843159603. Its totient is φ = 153375605712.

The previous prime is 181367812111. The next prime is 181367812133. The reversal of 181367812129 is 921218763181.

The square root of 181367812129 is 425873.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 177430500625 + 3937311504 = 421225^2 + 62748^2 .

It is not a de Polignac number, because 181367812129 - 2⁷ = 181367812001 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (181367512129) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 247431847 + ... + 247432579.

Almost surely, 2^181367812129 is an apocalyptic number.

181367812129 is the 425873-rd square number.

181367812129 is the 212937-th centered octagonal number.

It is an amenable number.

181367812129 is a deficient number, since it is larger than the sum of its proper divisors (32475347474).

181367812129 is an frugal number, since it uses more digits than its factorization.

181367812129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1646 (or 823 counting only the distinct ones).

The product of its digits is 290304, while the sum is 49.

Multiplying 181367812129 by its sum of digits (49), we get a square (8887022794321 = 2981111²).

181367812129 divided by its sum of digits (49) gives a square (3701383921 = 60839²).

The spelling of 181367812129 in words is "one hundred eighty-one billion, three hundred sixty-seven million, eight hundred twelve thousand, one hundred twenty-nine".