1661616403 has 2 divisors, whose sum is σ = 1661616404. Its totient is φ = 1661616402.

The previous prime is 1661616377. The next prime is 1661616413. The reversal of 1661616403 is 3046161661.

It is a strong prime.

It is an emirp because it is prime and its reverse (3046161661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1661616403 - 2⁵ = 1661616371 is a prime.

It is not a weakly prime, because it can be changed into another prime (1661616413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830808201 + 830808202.

It is an arithmetic number, because the mean of its divisors is an integer number (830808202).

Almost surely, 2^1661616403 is an apocalyptic number.

1661616403 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661616403 is an equidigital number, since it uses as much as digits as its factorization.

1661616403 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 1661616403 is about 40762.9292740353. The cubic root of 1661616403 is about 1184.4323399329.

The spelling of 1661616403 in words is "one billion, six hundred sixty-one million, six hundred sixteen thousand, four hundred three".