2173721929 has 2 divisors, whose sum is σ = 2173721930. Its totient is φ = 2173721928.

The previous prime is 2173721911. The next prime is 2173721951. The reversal of 2173721929 is 9291273712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1524746304 + 648975625 = 39048^2 + 25475^2 .

It is a cyclic number.

It is not a de Polignac number, because 2173721929 - 2⁷ = 2173721801 is a prime.

It is not a weakly prime, because it can be changed into another prime (2173721909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1086860964 + 1086860965.

It is an arithmetic number, because the mean of its divisors is an integer number (1086860965).

Almost surely, 2^2173721929 is an apocalyptic number.

It is an amenable number.

2173721929 is a deficient number, since it is larger than the sum of its proper divisors (1).

2173721929 is an equidigital number, since it uses as much as digits as its factorization.

2173721929 is an evil number, because the sum of its binary digits is even.

The product of its digits is 95256, while the sum is 43.

The square root of 2173721929 is about 46623.1908925161. The cubic root of 2173721929 is about 1295.3923527040.

The spelling of 2173721929 in words is "two billion, one hundred seventy-three million, seven hundred twenty-one thousand, nine hundred twenty-nine".