1681957 has 2 divisors, whose sum is σ = 1681958. Its totient is φ = 1681956.

The previous prime is 1681931. The next prime is 1681973. The reversal of 1681957 is 7591861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1522756 + 159201 = 1234^2 + 399^2 .

It is a cyclic number.

It is not a de Polignac number, because 1681957 - 2¹⁹ = 1157669 is a prime.

It is a Chen prime.

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1681907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 840978 + 840979.

It is an arithmetic number, because the mean of its divisors is an integer number (840979).

2^1681957 is an apocalyptic number.

It is an amenable number.

1681957 is a deficient number, since it is larger than the sum of its proper divisors (1).

1681957 is an equidigital number, since it uses as much as digits as its factorization.

1681957 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15120, while the sum is 37.

The square root of 1681957 is about 1296.9028490986. The cubic root of 1681957 is about 118.9245808864.

The spelling of 1681957 in words is "one million, six hundred eighty-one thousand, nine hundred fifty-seven".