1661815763 has 2 divisors, whose sum is σ = 1661815764. Its totient is φ = 1661815762.

The previous prime is 1661815747. The next prime is 1661815777. The reversal of 1661815763 is 3675181661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1661815763 - 2⁴ = 1661815747 is a prime.

It is not a weakly prime, because it can be changed into another prime (1661815783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830907881 + 830907882.

It is an arithmetic number, because the mean of its divisors is an integer number (830907882).

Almost surely, 2^1661815763 is an apocalyptic number.

1661815763 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661815763 is an equidigital number, since it uses as much as digits as its factorization.

1661815763 is an evil number, because the sum of its binary digits is even.

The product of its digits is 181440, while the sum is 44.

The square root of 1661815763 is about 40765.3745597903. The cubic root of 1661815763 is about 1184.4797072611.

The spelling of 1661815763 in words is "one billion, six hundred sixty-one million, eight hundred fifteen thousand, seven hundred sixty-three".