1985729 has 2 divisors, whose sum is σ = 1985730. Its totient is φ = 1985728.

The previous prime is 1985713. The next prime is 1985741. The reversal of 1985729 is 9275891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1495729 + 490000 = 1223^2 + 700^2 .

It is a cyclic number.

It is not a de Polignac number, because 1985729 - 2⁴ = 1985713 is a prime.

It is a super-2 number, since 2×1985729² = 7886239322882, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1985759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 992864 + 992865.

It is an arithmetic number, because the mean of its divisors is an integer number (992865).

2^1985729 is an apocalyptic number.

It is an amenable number.

1985729 is a deficient number, since it is larger than the sum of its proper divisors (1).

1985729 is an equidigital number, since it uses as much as digits as its factorization.

1985729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45360, while the sum is 41.

The square root of 1985729 is about 1409.1589690308. The cubic root of 1985729 is about 125.6917171583.

The spelling of 1985729 in words is "one million, nine hundred eighty-five thousand, seven hundred twenty-nine".