1601921 has 4 divisors (see below), whose sum is σ = 1628244. Its totient is φ = 1575600.

The previous prime is 1601869. The next prime is 1601953. The reversal of 1601921 is 1291061.

1601921 = T₁₉₈ + T₁₉₉ + ... + T₂₅₈.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1291061 = 569 ⋅2269.

It can be written as a sum of positive squares in 2 ways, for example, as 26896 + 1575025 = 164^2 + 1255^2 .

It is a cyclic number.

It is not a de Polignac number, because 1601921 - 2⁶ = 1601857 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1601893 and 1601902.

It is not an unprimeable number, because it can be changed into a prime (1601521) 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, 13070 + ... + 13191.

It is an arithmetic number, because the mean of its divisors is an integer number (407061).

2^1601921 is an apocalyptic number.

It is an amenable number.

1601921 is a deficient number, since it is larger than the sum of its proper divisors (26323).

1601921 is an equidigital number, since it uses as much as digits as its factorization.

1601921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26322.

The product of its (nonzero) digits is 108, while the sum is 20.

The square root of 1601921 is about 1265.6701782060. The cubic root of 1601921 is about 117.0074994584.

Adding to 1601921 its reverse (1291061), we get a palindrome (2892982).

The spelling of 1601921 in words is "one million, six hundred one thousand, nine hundred twenty-one".