1685557397 has 2 divisors, whose sum is σ = 1685557398. Its totient is φ = 1685557396.

The previous prime is 1685557333. The next prime is 1685557417. The reversal of 1685557397 is 7937555861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1302415921 + 383141476 = 36089^2 + 19574^2 .

It is a cyclic number.

It is not a de Polignac number, because 1685557397 - 2⁶ = 1685557333 is a prime.

It is a super-2 number, since 2×1685557397² = 5682207477162831218, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1685557297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 842778698 + 842778699.

It is an arithmetic number, because the mean of its divisors is an integer number (842778699).

Almost surely, 2^1685557397 is an apocalyptic number.

It is an amenable number.

1685557397 is a deficient number, since it is larger than the sum of its proper divisors (1).

1685557397 is an equidigital number, since it uses as much as digits as its factorization.

1685557397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7938000, while the sum is 56.

The square root of 1685557397 is about 41055.5403934719. The cubic root of 1685557397 is about 1190.0937705926.

The spelling of 1685557397 in words is "one billion, six hundred eighty-five million, five hundred fifty-seven thousand, three hundred ninety-seven".