1661397103 has 2 divisors, whose sum is σ = 1661397104. Its totient is φ = 1661397102.

The previous prime is 1661397013. The next prime is 1661397113. The reversal of 1661397103 is 3017931661.

Together with previous prime (1661397013) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1661397103 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1661397113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830698551 + 830698552.

It is an arithmetic number, because the mean of its divisors is an integer number (830698552).

Almost surely, 2^1661397103 is an apocalyptic number.

1661397103 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661397103 is an equidigital number, since it uses as much as digits as its factorization.

1661397103 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20412, while the sum is 37.

The square root of 1661397103 is about 40760.2392412017. The cubic root of 1661397103 is about 1184.3802305452.

The spelling of 1661397103 in words is "one billion, six hundred sixty-one million, three hundred ninety-seven thousand, one hundred three".