1697740621 has 2 divisors, whose sum is σ = 1697740622. Its totient is φ = 1697740620.

The previous prime is 1697740619. The next prime is 1697740643. The reversal of 1697740621 is 1260477961.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1595123721 + 102616900 = 39939^2 + 10130^2 .

It is an emirp because it is prime and its reverse (1260477961) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1697740621 - 2¹ = 1697740619 is a prime.

Together with 1697740619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1697770621) 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, 848870310 + 848870311.

It is an arithmetic number, because the mean of its divisors is an integer number (848870311).

Almost surely, 2^1697740621 is an apocalyptic number.

It is an amenable number.

1697740621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1697740621 is an equidigital number, since it uses as much as digits as its factorization.

1697740621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 127008, while the sum is 43.

The square root of 1697740621 is about 41203.6481515897. The cubic root of 1697740621 is about 1192.9542259767.

The spelling of 1697740621 in words is "one billion, six hundred ninety-seven million, seven hundred forty thousand, six hundred twenty-one".