1281172405 has 4 divisors (see below), whose sum is σ = 1537406892. Its totient is φ = 1024937920.

The previous prime is 1281172307. The next prime is 1281172421. The reversal of 1281172405 is 5042711821.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 207561649 + 1073610756 = 14407^2 + 32766^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1281172405 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 128117236 + ... + 128117245.

It is an arithmetic number, because the mean of its divisors is an integer number (384351723).

Almost surely, 2^1281172405 is an apocalyptic number.

It is an amenable number.

1281172405 is a deficient number, since it is larger than the sum of its proper divisors (256234487).

1281172405 is an equidigital number, since it uses as much as digits as its factorization.

1281172405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256234486.

The product of its (nonzero) digits is 4480, while the sum is 31.

The square root of 1281172405 is about 35793.4687478037. The cubic root of 1281172405 is about 1086.0984451432.

The spelling of 1281172405 in words is "one billion, two hundred eighty-one million, one hundred seventy-two thousand, four hundred five".