1591649 has 6 divisors (see below), whose sum is σ = 1680210. Its totient is φ = 1507536.

The previous prime is 1591637. The next prime is 1591663. The reversal of 1591649 is 9461951.

It can be written as a sum of positive squares in only one way, i.e., 1014049 + 577600 = 1007^2 + 760^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1591649 is a prime.

It is a d-powerful number, because it can be written as 1 + 5⁵ + 9³ + 1 + 6⁵ + 4¹⁰ + 9⁶ .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1591949) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1844 + ... + 2565.

It is an arithmetic number, because the mean of its divisors is an integer number (280035).

2^1591649 is an apocalyptic number.

1591649 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

1591649 is a deficient number, since it is larger than the sum of its proper divisors (88561).

1591649 is an equidigital number, since it uses as much as digits as its factorization.

1591649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4447 (or 4428 counting only the distinct ones).

The product of its digits is 9720, while the sum is 35.

The square root of 1591649 is about 1261.6057228786. The cubic root of 1591649 is about 116.7568672052.

The spelling of 1591649 in words is "one million, five hundred ninety-one thousand, six hundred forty-nine".