2179721771 has 2 divisors, whose sum is σ = 2179721772. Its totient is φ = 2179721770.

The previous prime is 2179721711. The next prime is 2179721779. The reversal of 2179721771 is 1771279712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2179721771 - 2¹⁸ = 2179459627 is a prime.

It is not a weakly prime, because it can be changed into another prime (2179721779) 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, 1089860885 + 1089860886.

It is an arithmetic number, because the mean of its divisors is an integer number (1089860886).

Almost surely, 2^2179721771 is an apocalyptic number.

2179721771 is a deficient number, since it is larger than the sum of its proper divisors (1).

2179721771 is an equidigital number, since it uses as much as digits as its factorization.

2179721771 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 86436, while the sum is 44.

The square root of 2179721771 is about 46687.4905194100. The cubic root of 2179721771 is about 1296.5830921860.

The spelling of 2179721771 in words is "two billion, one hundred seventy-nine million, seven hundred twenty-one thousand, seven hundred seventy-one".