1543643 has 4 divisors (see below), whose sum is σ = 1551600. Its totient is φ = 1535688.

The previous prime is 1543639. The next prime is 1543649. The reversal of 1543643 is 3463451.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3463451 = 71 ⋅48781.

It is a cyclic number.

It is not a de Polignac number, because 1543643 - 2² = 1543639 is a prime.

It is a super-2 number, since 2×1543643² = 4765667422898, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1543649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3680 + ... + 4077.

It is an arithmetic number, because the mean of its divisors is an integer number (387900).

2^1543643 is an apocalyptic number.

1543643 is a deficient number, since it is larger than the sum of its proper divisors (7957).

1543643 is an equidigital number, since it uses as much as digits as its factorization.

1543643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7956.

The product of its digits is 4320, while the sum is 26.

The square root of 1543643 is about 1242.4343040982. The cubic root of 1543643 is about 115.5710225776.

The spelling of 1543643 in words is "one million, five hundred forty-three thousand, six hundred forty-three".