1701721661 has 4 divisors (see below), whose sum is σ = 1701814524. Its totient is φ = 1701628800.

The previous prime is 1701721639. The next prime is 1701721673. The reversal of 1701721661 is 1661271071.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 913852900 + 787868761 = 30230^2 + 28069^2 .

It is a cyclic number.

It is not a de Polignac number, because 1701721661 - 2⁶ = 1701721597 is a prime.

It is a super-2 number, since 2×1701721661² = 5791713223033197842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1701721961) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8750 + ... + 58991.

It is an arithmetic number, because the mean of its divisors is an integer number (425453631).

Almost surely, 2^1701721661 is an apocalyptic number.

It is an amenable number.

1701721661 is a deficient number, since it is larger than the sum of its proper divisors (92863).

1701721661 is an equidigital number, since it uses as much as digits as its factorization.

1701721661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92862.

The product of its (nonzero) digits is 3528, while the sum is 32.

The square root of 1701721661 is about 41251.9291791305. The cubic root of 1701721661 is about 1193.8859527517.

The spelling of 1701721661 in words is "one billion, seven hundred one million, seven hundred twenty-one thousand, six hundred sixty-one".