1257021643 has 4 divisors (see below), whose sum is σ = 1257137200. Its totient is φ = 1256906088.

The previous prime is 1257021629. The next prime is 1257021707. The reversal of 1257021643 is 3461207521.

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

It is a cyclic number.

It is not a de Polignac number, because 1257021643 - 2⁵ = 1257021611 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1257021613) 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, 39543 + ... + 63856.

It is an arithmetic number, because the mean of its divisors is an integer number (314284300).

Almost surely, 2^1257021643 is an apocalyptic number.

1257021643 is a deficient number, since it is larger than the sum of its proper divisors (115557).

1257021643 is a wasteful number, since it uses less digits than its factorization.

1257021643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115556.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 1257021643 is about 35454.5010259628. The cubic root of 1257021643 is about 1079.2306028424.

The spelling of 1257021643 in words is "one billion, two hundred fifty-seven million, twenty-one thousand, six hundred forty-three".