1913921 has 4 divisors (see below), whose sum is σ = 1960644. Its totient is φ = 1867200.

The previous prime is 1913917. The next prime is 1913939. The reversal of 1913921 is 1293191.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1293191 = 373 ⋅3467.

It can be written as a sum of positive squares in 2 ways, for example, as 1123600 + 790321 = 1060^2 + 889^2 .

It is a cyclic number.

It is not a de Polignac number, because 1913921 - 2² = 1913917 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1913941) 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, 23300 + ... + 23381.

It is an arithmetic number, because the mean of its divisors is an integer number (490161).

2^1913921 is an apocalyptic number.

It is an amenable number.

1913921 is a deficient number, since it is larger than the sum of its proper divisors (46723).

1913921 is an equidigital number, since it uses as much as digits as its factorization.

1913921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46722.

The product of its digits is 486, while the sum is 26.

The square root of 1913921 is about 1383.4453368312. The cubic root of 1913921 is about 124.1579888735.

The spelling of 1913921 in words is "one million, nine hundred thirteen thousand, nine hundred twenty-one".