1256536505 has 16 divisors (see below), whose sum is σ = 1782673920. Its totient is φ = 831913152.

The previous prime is 1256536451. The next prime is 1256536513. The reversal of 1256536505 is 5056356521.

It is not a de Polignac number, because 1256536505 - 2⁶ = 1256536441 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 617969 + ... + 619998.

It is an arithmetic number, because the mean of its divisors is an integer number (111417120).

Almost surely, 2^1256536505 is an apocalyptic number.

It is an amenable number.

1256536505 is a deficient number, since it is larger than the sum of its proper divisors (526137415).

1256536505 is a wasteful number, since it uses less digits than its factorization.

1256536505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1238008.

The product of its (nonzero) digits is 135000, while the sum is 38.

The square root of 1256536505 is about 35447.6586673930. The cubic root of 1256536505 is about 1079.0917446798.

The spelling of 1256536505 in words is "one billion, two hundred fifty-six million, five hundred thirty-six thousand, five hundred five".