1601891 has 4 divisors (see below), whose sum is σ = 1607952. Its totient is φ = 1595832.

The previous prime is 1601869. The next prime is 1601953. The reversal of 1601891 is 1981061.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1981061 = 17 ⋅116533.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1601891 is a prime.

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 1601891.

It is not an unprimeable number, because it can be changed into a prime (1601861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2615 + ... + 3168.

It is an arithmetic number, because the mean of its divisors is an integer number (401988).

2^1601891 is an apocalyptic number.

1601891 is a deficient number, since it is larger than the sum of its proper divisors (6061).

1601891 is an equidigital number, since it uses as much as digits as its factorization.

1601891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6060.

The product of its (nonzero) digits is 432, while the sum is 26.

The square root of 1601891 is about 1265.6583267217. The cubic root of 1601891 is about 117.0067690339.

The spelling of 1601891 in words is "one million, six hundred one thousand, eight hundred ninety-one".