1863721 has 2 divisors, whose sum is σ = 1863722. Its totient is φ = 1863720.

The previous prime is 1863707. The next prime is 1863731. The reversal of 1863721 is 1273681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1795600 + 68121 = 1340^2 + 261^2 .

It is an emirp because it is prime and its reverse (1273681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1863721 - 2⁷ = 1863593 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1863721.

It is not a weakly prime, because it can be changed into another prime (1863731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 931860 + 931861.

It is an arithmetic number, because the mean of its divisors is an integer number (931861).

2^1863721 is an apocalyptic number.

It is an amenable number.

1863721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1863721 is an equidigital number, since it uses as much as digits as its factorization.

1863721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2016, while the sum is 28.

The square root of 1863721 is about 1365.1816728919. The cubic root of 1863721 is about 123.0628493222.

The spelling of 1863721 in words is "one million, eight hundred sixty-three thousand, seven hundred twenty-one".