1256513745 has 16 divisors (see below), whose sum is σ = 2053198080. Its totient is φ = 655881984.

The previous prime is 1256513729. The next prime is 1256513761. The reversal of 1256513745 is 5473156521.

It is an interprime number because it is at equal distance from previous prime (1256513729) and next prime (1256513761).

It is not a de Polignac number, because 1256513745 - 2⁴ = 1256513729 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 890440 + ... + 891849.

It is an arithmetic number, because the mean of its divisors is an integer number (128324880).

Almost surely, 2^1256513745 is an apocalyptic number.

1256513745 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1256513745 is a deficient number, since it is larger than the sum of its proper divisors (796684335).

1256513745 is a wasteful number, since it uses less digits than its factorization.

1256513745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1782344.

The product of its digits is 126000, while the sum is 39.

The square root of 1256513745 is about 35447.3376292212. The cubic root of 1256513745 is about 1079.0852293427.

The spelling of 1256513745 in words is "one billion, two hundred fifty-six million, five hundred thirteen thousand, seven hundred forty-five".