1815641 has 4 divisors (see below), whose sum is σ = 1818852. Its totient is φ = 1812432.

The previous prime is 1815637. The next prime is 1815647. The reversal of 1815641 is 1465181.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1449616 + 366025 = 1204^2 + 605^2 .

It is a cyclic number.

It is not a de Polignac number, because 1815641 - 2² = 1815637 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 1815641.

It is not an unprimeable number, because it can be changed into a prime (1815647) 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, 506 + ... + 1971.

It is an arithmetic number, because the mean of its divisors is an integer number (454713).

2^1815641 is an apocalyptic number.

It is an amenable number.

1815641 is a deficient number, since it is larger than the sum of its proper divisors (3211).

1815641 is an equidigital number, since it uses as much as digits as its factorization.

1815641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3210.

The product of its digits is 960, while the sum is 26.

The square root of 1815641 is about 1347.4572349429. The cubic root of 1815641 is about 121.9953639733.

The spelling of 1815641 in words is "one million, eight hundred fifteen thousand, six hundred forty-one".