1661835121 has 2 divisors, whose sum is σ = 1661835122. Its totient is φ = 1661835120.

The previous prime is 1661835101. The next prime is 1661835127. The reversal of 1661835121 is 1215381661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1525996096 + 135839025 = 39064^2 + 11655^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661835121 - 2⁵ = 1661835089 is a prime.

It is not a weakly prime, because it can be changed into another prime (1661835127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830917560 + 830917561.

It is an arithmetic number, because the mean of its divisors is an integer number (830917561).

Almost surely, 2^1661835121 is an apocalyptic number.

It is an amenable number.

1661835121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661835121 is an equidigital number, since it uses as much as digits as its factorization.

1661835121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 34.

The square root of 1661835121 is about 40765.6119909906. The cubic root of 1661835121 is about 1184.4843064611.

The spelling of 1661835121 in words is "one billion, six hundred sixty-one million, eight hundred thirty-five thousand, one hundred twenty-one".