1998541 has 2 divisors, whose sum is σ = 1998542. Its totient is φ = 1998540.

The previous prime is 1998533. The next prime is 1998559. The reversal of 1998541 is 1458991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1612900 + 385641 = 1270^2 + 621^2 .

It is a cyclic number.

It is not a de Polignac number, because 1998541 - 2³ = 1998533 is a prime.

It is a super-2 number, since 2×1998541² = 7988332257362, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1998541.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1998041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999270 + 999271.

It is an arithmetic number, because the mean of its divisors is an integer number (999271).

2^1998541 is an apocalyptic number.

It is an amenable number.

1998541 is a deficient number, since it is larger than the sum of its proper divisors (1).

1998541 is an equidigital number, since it uses as much as digits as its factorization.

1998541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 37.

The square root of 1998541 is about 1413.6976338666. The cubic root of 1998541 is about 125.9614604564.

The spelling of 1998541 in words is "one million, nine hundred ninety-eight thousand, five hundred forty-one".