1281725161 has 4 divisors (see below), whose sum is σ = 1349184400. Its totient is φ = 1214265924.

The previous prime is 1281725153. The next prime is 1281725189. The reversal of 1281725161 is 1615271821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1615271821 = 4889 ⋅330389.

It is a cyclic number.

It is not a de Polignac number, because 1281725161 - 2³ = 1281725153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1281725131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33729591 + ... + 33729628.

It is an arithmetic number, because the mean of its divisors is an integer number (337296100).

Almost surely, 2^1281725161 is an apocalyptic number.

It is an amenable number.

1281725161 is a deficient number, since it is larger than the sum of its proper divisors (67459239).

1281725161 is an equidigital number, since it uses as much as digits as its factorization.

1281725161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67459238.

The product of its digits is 6720, while the sum is 34.

The square root of 1281725161 is about 35801.1893796840. The cubic root of 1281725161 is about 1086.2546200945.

Adding to 1281725161 its reverse (1615271821), we get a palindrome (2896996982).

The spelling of 1281725161 in words is "one billion, two hundred eighty-one million, seven hundred twenty-five thousand, one hundred sixty-one".