1657557541021 has 2 divisors, whose sum is σ = 1657557541022. Its totient is φ = 1657557541020.

The previous prime is 1657557540967. The next prime is 1657557541033. The reversal of 1657557541021 is 1201457557561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1379602939225 + 277954601796 = 1174565^2 + 527214^2 .

It is a cyclic number.

It is not a de Polignac number, because 1657557541021 - 2²⁵ = 1657523986589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1657557541051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 828778770510 + 828778770511.

It is an arithmetic number, because the mean of its divisors is an integer number (828778770511).

Almost surely, 2^{1657557541021} is an apocalyptic number.

It is an amenable number.

1657557541021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1657557541021 is an equidigital number, since it uses as much as digits as its factorization.

1657557541021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1470000, while the sum is 49.

The spelling of 1657557541021 in words is "one trillion, six hundred fifty-seven billion, five hundred fifty-seven million, five hundred forty-one thousand, twenty-one".