1257915139 has 4 divisors (see below), whose sum is σ = 1354677856. Its totient is φ = 1161152424.

The previous prime is 1257915101. The next prime is 1257915143. The reversal of 1257915139 is 9315197521.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9315197521 = 7 ⋅1330742503.

It is a cyclic number.

It is not a de Polignac number, because 1257915139 - 2¹¹ = 1257913091 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1257915095 and 1257915104.

It is not an unprimeable number, because it can be changed into a prime (1257915739) 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, 48381339 + ... + 48381364.

It is an arithmetic number, because the mean of its divisors is an integer number (338669464).

Almost surely, 2^1257915139 is an apocalyptic number.

1257915139 is a deficient number, since it is larger than the sum of its proper divisors (96762717).

1257915139 is an equidigital number, since it uses as much as digits as its factorization.

1257915139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96762716.

The product of its digits is 85050, while the sum is 43.

The square root of 1257915139 is about 35467.0993880244. The cubic root of 1257915139 is about 1079.4862494202.

The spelling of 1257915139 in words is "one billion, two hundred fifty-seven million, nine hundred fifteen thousand, one hundred thirty-nine".