1257532657 has 4 divisors (see below), whose sum is σ = 1257969636. Its totient is φ = 1257095680.

The previous prime is 1257532649. The next prime is 1257532663. The reversal of 1257532657 is 7562357521.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 263770081 + 993762576 = 16241^2 + 31524^2 .

It is a cyclic number.

It is not a de Polignac number, because 1257532657 - 2³ = 1257532649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1257532637) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 214144 + ... + 219937.

It is an arithmetic number, because the mean of its divisors is an integer number (314492409).

Almost surely, 2^1257532657 is an apocalyptic number.

It is an amenable number.

1257532657 is a deficient number, since it is larger than the sum of its proper divisors (436979).

1257532657 is an equidigital number, since it uses as much as digits as its factorization.

1257532657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 436978.

The product of its digits is 441000, while the sum is 43.

The square root of 1257532657 is about 35461.7069104125. The cubic root of 1257532657 is about 1079.3768287073.

The spelling of 1257532657 in words is "one billion, two hundred fifty-seven million, five hundred thirty-two thousand, six hundred fifty-seven".