1257701689729 has 27 divisors (see below), whose sum is σ = 1370268709851. Its totient is φ = 1154130293760.

The previous prime is 1257701689679. The next prime is 1257701689747. The reversal of 1257701689729 is 9279861077521.

The square root of 1257701689729 is 1121473.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 13 ways, for example, as 207585028225 + 1050116661504 = 455615^2 + 1024752^2 .

It is not a de Polignac number, because 1257701689729 - 2²¹ = 1257699592577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1257701689759) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 781665877 + ... + 781667485.

Almost surely, 2^{1257701689729} is an apocalyptic number.

1257701689729 is the 1121473-rd square number.

1257701689729 is the 560737-th centered octagonal number.

It is an amenable number.

1257701689729 is a deficient number, since it is larger than the sum of its proper divisors (112567020122).

1257701689729 is an frugal number, since it uses more digits than its factorization.

1257701689729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3334 (or 1667 counting only the distinct ones).

The product of its (nonzero) digits is 26671680, while the sum is 64.

Multiplying 1257701689729 by its sum of digits (64), we get a square (80492908142656 = 8971784²).

The spelling of 1257701689729 in words is "one trillion, two hundred fifty-seven billion, seven hundred one million, six hundred eighty-nine thousand, seven hundred twenty-nine".