1280406745 has 4 divisors (see below), whose sum is σ = 1536488100. Its totient is φ = 1024325392.

The previous prime is 1280406737. The next prime is 1280406763. The reversal of 1280406745 is 5476040821.

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 381186576 + 899220169 = 19524^2 + 29987^2 .

It is a cyclic number.

It is not a de Polignac number, because 1280406745 - 2³ = 1280406737 is a prime.

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, 128040670 + ... + 128040679.

It is an arithmetic number, because the mean of its divisors is an integer number (384122025).

Almost surely, 2^1280406745 is an apocalyptic number.

It is an amenable number.

1280406745 is a deficient number, since it is larger than the sum of its proper divisors (256081355).

1280406745 is an equidigital number, since it uses as much as digits as its factorization.

1280406745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256081354.

The product of its (nonzero) digits is 53760, while the sum is 37.

The square root of 1280406745 is about 35782.7716226678. The cubic root of 1280406745 is about 1085.8820423533.

The spelling of 1280406745 in words is "one billion, two hundred eighty million, four hundred six thousand, seven hundred forty-five".