13406166225 has 135 divisors (see below), whose sum is σ = 25972632939. Its totient is φ = 6835946400.

The previous prime is 13406166223. The next prime is 13406166269. The reversal of 13406166225 is 52266160431.

The square root of 13406166225 is 115785.

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

13406166225 is a `hidden beast` number, since 1 + 34 + 0 + 616 + 6 + 2 + 2 + 5 = 666.

It can be written as a sum of positive squares in only one way, i.e., 4826219841 + 8579946384 = 69471^2 + 92628^2 .

It is a tau number, because it is divible by the number of its divisors (135).

It is not a de Polignac number, because 13406166225 - 2¹ = 13406166223 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 13406166225.

It is not an unprimeable number, because it can be changed into a prime (13406166223) by changing a digit.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 161520034 + ... + 161520116.

Almost surely, 2^13406166225 is an apocalyptic number.

13406166225 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

13406166225 is the 115785-th square number.

13406166225 is the 57893-rd centered octagonal number.

It is an amenable number.

13406166225 is a deficient number, since it is larger than the sum of its proper divisors (12566466714).

13406166225 is an frugal number, since it uses more digits than its factorization.

13406166225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250 (or 122 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

Multiplying 13406166225 by its sum of digits (36), we get a square (482621984100 = 694710²).

The spelling of 13406166225 in words is "thirteen billion, four hundred six million, one hundred sixty-six thousand, two hundred twenty-five".