8161354921 has 2 divisors, whose sum is σ = 8161354922. Its totient is φ = 8161354920.

The previous prime is 8161354919. The next prime is 8161354933. The reversal of 8161354921 is 1294531618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6763417600 + 1397937321 = 82240^2 + 37389^2 .

It is a cyclic number.

It is not a de Polignac number, because 8161354921 - 2¹ = 8161354919 is a prime.

Together with 8161354919, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (8161354991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4080677460 + 4080677461.

It is an arithmetic number, because the mean of its divisors is an integer number (4080677461).

Almost surely, 2^8161354921 is an apocalyptic number.

It is an amenable number.

8161354921 is a deficient number, since it is larger than the sum of its proper divisors (1).

8161354921 is an equidigital number, since it uses as much as digits as its factorization.

8161354921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 40.

The square root of 8161354921 is about 90340.2176275882. The cubic root of 8161354921 is about 2013.3568422220.

The spelling of 8161354921 in words is "eight billion, one hundred sixty-one million, three hundred fifty-four thousand, nine hundred twenty-one".