1601665787 has 2 divisors, whose sum is σ = 1601665788. Its totient is φ = 1601665786.

The previous prime is 1601665733. The next prime is 1601665811. The reversal of 1601665787 is 7875661061.

It is a strong prime.

It is an emirp because it is prime and its reverse (7875661061) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1601665787 - 2⁸ = 1601665531 is a prime.

It is not a weakly prime, because it can be changed into another prime (1601664787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 800832893 + 800832894.

It is an arithmetic number, because the mean of its divisors is an integer number (800832894).

Almost surely, 2^1601665787 is an apocalyptic number.

1601665787 is a deficient number, since it is larger than the sum of its proper divisors (1).

1601665787 is an equidigital number, since it uses as much as digits as its factorization.

1601665787 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 423360, while the sum is 47.

The square root of 1601665787 is about 40020.8169206977. The cubic root of 1601665787 is about 1170.0128537317.

The spelling of 1601665787 in words is "one billion, six hundred one million, six hundred sixty-five thousand, seven hundred eighty-seven".