1257620457 has 4 divisors (see below), whose sum is σ = 1676827280. Its totient is φ = 838413636.

The previous prime is 1257620449. The next prime is 1257620471. The reversal of 1257620457 is 7540267521.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1257620457 - 2³ = 1257620449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1257620437) 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, 209603407 + ... + 209603412.

It is an arithmetic number, because the mean of its divisors is an integer number (419206820).

Almost surely, 2^1257620457 is an apocalyptic number.

It is an amenable number.

1257620457 is a deficient number, since it is larger than the sum of its proper divisors (419206823).

1257620457 is an equidigital number, since it uses as much as digits as its factorization.

1257620457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 419206822.

The product of its (nonzero) digits is 117600, while the sum is 39.

The square root of 1257620457 is about 35462.9448438789. The cubic root of 1257620457 is about 1079.4019485533.

Adding to 1257620457 its reverse (7540267521), we get a palindrome (8797887978).

It can be divided in two parts, 12576 and 20457, that added together give a palindrome (33033).

The spelling of 1257620457 in words is "one billion, two hundred fifty-seven million, six hundred twenty thousand, four hundred fifty-seven".