1601721941 has 2 divisors, whose sum is σ = 1601721942. Its totient is φ = 1601721940.

The previous prime is 1601721833. The next prime is 1601721943. The reversal of 1601721941 is 1491271061.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1336194916 + 265527025 = 36554^2 + 16295^2 .

It is a cyclic number.

It is not a de Polignac number, because 1601721941 - 2²² = 1597527637 is a prime.

Together with 1601721943, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 1601721898 and 1601721907.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1601721943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 800860970 + 800860971.

It is an arithmetic number, because the mean of its divisors is an integer number (800860971).

Almost surely, 2^1601721941 is an apocalyptic number.

It is an amenable number.

1601721941 is a deficient number, since it is larger than the sum of its proper divisors (1).

1601721941 is an equidigital number, since it uses as much as digits as its factorization.

1601721941 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 32.

The square root of 1601721941 is about 40021.5184744407. The cubic root of 1601721941 is about 1170.0265270241.

The spelling of 1601721941 in words is "one billion, six hundred one million, seven hundred twenty-one thousand, nine hundred forty-one".