1640557 has 2 divisors, whose sum is σ = 1640558. Its totient is φ = 1640556.

The previous prime is 1640549. The next prime is 1640599. The reversal of 1640557 is 7550461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1320201 + 320356 = 1149^2 + 566^2 .

It is an emirp because it is prime and its reverse (7550461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1640557 - 2³ = 1640549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1640057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820278 + 820279.

It is an arithmetic number, because the mean of its divisors is an integer number (820279).

2^1640557 is an apocalyptic number.

It is an amenable number.

1640557 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640557 is an equidigital number, since it uses as much as digits as its factorization.

1640557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4200, while the sum is 28.

The square root of 1640557 is about 1280.8423009879. The cubic root of 1640557 is about 117.9407200089.

It can be divided in two parts, 1640 and 557, that added together give a cube (2197 = 13³).

The spelling of 1640557 in words is "one million, six hundred forty thousand, five hundred fifty-seven".