1257021613 has 2 divisors, whose sum is σ = 1257021614. Its totient is φ = 1257021612.

The previous prime is 1257021611. The next prime is 1257021629. The reversal of 1257021613 is 3161207521.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 737774244 + 519247369 = 27162^2 + 22787^2 .

It is a cyclic number.

It is not a de Polignac number, because 1257021613 - 2¹ = 1257021611 is a prime.

Together with 1257021611, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1257021611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628510806 + 628510807.

It is an arithmetic number, because the mean of its divisors is an integer number (628510807).

Almost surely, 2^1257021613 is an apocalyptic number.

It is an amenable number.

1257021613 is a deficient number, since it is larger than the sum of its proper divisors (1).

1257021613 is an equidigital number, since it uses as much as digits as its factorization.

1257021613 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 1257021613 is about 35454.5006028854. The cubic root of 1257021613 is about 1079.2305942568.

The spelling of 1257021613 in words is "one billion, two hundred fifty-seven million, twenty-one thousand, six hundred thirteen".