1543045661 has 4 divisors (see below), whose sum is σ = 1543672092. Its totient is φ = 1542419232.

The previous prime is 1543045649. The next prime is 1543045667. The reversal of 1543045661 is 1665403451.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1665403451 = 127 ⋅13113413.

It can be written as a sum of positive squares in 2 ways, for example, as 400200025 + 1142845636 = 20005^2 + 33806^2 .

It is a cyclic number.

It is not a de Polignac number, because 1543045661 - 2³⁰ = 469303837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1543045667) 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, 309506 + ... + 314451.

It is an arithmetic number, because the mean of its divisors is an integer number (385918023).

Almost surely, 2^1543045661 is an apocalyptic number.

It is an amenable number.

1543045661 is a deficient number, since it is larger than the sum of its proper divisors (626431).

1543045661 is an equidigital number, since it uses as much as digits as its factorization.

1543045661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 626430.

The product of its (nonzero) digits is 43200, while the sum is 35.

The square root of 1543045661 is about 39281.6198876777. The cubic root of 1543045661 is about 1155.5611326123.

The spelling of 1543045661 in words is "one billion, five hundred forty-three million, forty-five thousand, six hundred sixty-one".