1661459603 has 4 divisors (see below), whose sum is σ = 1665095640. Its totient is φ = 1657823568.

The previous prime is 1661459587. The next prime is 1661459621. The reversal of 1661459603 is 3069541661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3069541661 = 12659 ⋅242479.

It is a cyclic number.

It is not a de Polignac number, because 1661459603 - 2⁴ = 1661459587 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661452603) 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, 1817333 + ... + 1818246.

It is an arithmetic number, because the mean of its divisors is an integer number (416273910).

Almost surely, 2^1661459603 is an apocalyptic number.

1661459603 is a deficient number, since it is larger than the sum of its proper divisors (3636037).

1661459603 is an equidigital number, since it uses as much as digits as its factorization.

1661459603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3636036.

The product of its (nonzero) digits is 116640, while the sum is 41.

The square root of 1661459603 is about 40761.0059125140. The cubic root of 1661459603 is about 1184.3950820691.

The spelling of 1661459603 in words is "one billion, six hundred sixty-one million, four hundred fifty-nine thousand, six hundred three".