1557641 has 2 divisors, whose sum is σ = 1557642. Its totient is φ = 1557640.

The previous prime is 1557637. The next prime is 1557649. The reversal of 1557641 is 1467551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 883600 + 674041 = 940^2 + 821^2 .

It is a cyclic number.

It is not a de Polignac number, because 1557641 - 2² = 1557637 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1557649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 778820 + 778821.

It is an arithmetic number, because the mean of its divisors is an integer number (778821).

2^1557641 is an apocalyptic number.

It is an amenable number.

1557641 is a deficient number, since it is larger than the sum of its proper divisors (1).

1557641 is an equidigital number, since it uses as much as digits as its factorization.

1557641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4200, while the sum is 29.

The square root of 1557641 is about 1248.0548866136. The cubic root of 1557641 is about 115.9193107110.

The spelling of 1557641 in words is "one million, five hundred fifty-seven thousand, six hundred forty-one".