1620591 has 8 divisors (see below), whose sum is σ = 2469504. Its totient is φ = 926040.

The previous prime is 1620589. The next prime is 1620611. The reversal of 1620591 is 1950261.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1620591 - 2¹ = 1620589 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1620551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38565 + ... + 38606.

It is an arithmetic number, because the mean of its divisors is an integer number (308688).

2^1620591 is an apocalyptic number.

1620591 is a deficient number, since it is larger than the sum of its proper divisors (848913).

1620591 is an equidigital number, since it uses as much as digits as its factorization.

1620591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77181.

The product of its (nonzero) digits is 540, while the sum is 24.

The square root of 1620591 is about 1273.0243516917. The cubic root of 1620591 is about 117.4603095158.

It can be divided in two parts, 1620 and 591, that added together give a triangular number (2211 = T₆₆).

The spelling of 1620591 in words is "one million, six hundred twenty thousand, five hundred ninety-one".