1985591 has 2 divisors, whose sum is σ = 1985592. Its totient is φ = 1985590.

The previous prime is 1985587. The next prime is 1985593. The reversal of 1985591 is 1955891.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1985591 - 2² = 1985587 is a prime.

Together with 1985593, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1985593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 992795 + 992796.

It is an arithmetic number, because the mean of its divisors is an integer number (992796).

2^1985591 is an apocalyptic number.

1985591 is a deficient number, since it is larger than the sum of its proper divisors (1).

1985591 is an equidigital number, since it uses as much as digits as its factorization.

1985591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16200, while the sum is 38.

The square root of 1985591 is about 1409.1100028032. The cubic root of 1985591 is about 125.6888054051.

The spelling of 1985591 in words is "one million, nine hundred eighty-five thousand, five hundred ninety-one".