1257681 has 8 divisors (see below), whose sum is σ = 1690624. Its totient is φ = 831600.

The previous prime is 1257653. The next prime is 1257689. The reversal of 1257681 is 1867521.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1257681 - 2¹¹ = 1255633 is a prime.

It is a super-2 number, since 2×1257681² = 3163522995522, which contains 22 as substring.

1257681 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1257689) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1270 + ... + 2031.

It is an arithmetic number, because the mean of its divisors is an integer number (211328).

2^1257681 is an apocalyptic number.

It is an amenable number.

1257681 is a deficient number, since it is larger than the sum of its proper divisors (432943).

1257681 is a wasteful number, since it uses less digits than its factorization.

1257681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3431.

The product of its digits is 3360, while the sum is 30.

The square root of 1257681 is about 1121.4637756076. The cubic root of 1257681 is about 107.9419269408.

The spelling of 1257681 in words is "one million, two hundred fifty-seven thousand, six hundred eighty-one".