1620791 has 4 divisors (see below), whose sum is σ = 1624584. Its totient is φ = 1617000.

The previous prime is 1620769. The next prime is 1620803. The reversal of 1620791 is 1970261.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1620791 - 2¹⁸ = 1358647 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1620791.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1620391) 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 3 ways as a sum of consecutive naturals, for example, 1160 + ... + 2141.

It is an arithmetic number, because the mean of its divisors is an integer number (406146).

2^1620791 is an apocalyptic number.

1620791 is a deficient number, since it is larger than the sum of its proper divisors (3793).

1620791 is an equidigital number, since it uses as much as digits as its factorization.

1620791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3792.

The product of its (nonzero) digits is 756, while the sum is 26.

The square root of 1620791 is about 1273.1029023610. The cubic root of 1620791 is about 117.4651413118.

The spelling of 1620791 in words is "one million, six hundred twenty thousand, seven hundred ninety-one".