1618921 has 8 divisors (see below), whose sum is σ = 1670624. Its totient is φ = 1568160.

The previous prime is 1618909. The next prime is 1618931. The reversal of 1618921 is 1298161.

1618921 = 24² + 25² + ... + 169².

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1618921 - 2¹⁹ = 1094633 is a prime.

It is an alternating number because its digits alternate between odd and even.

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 1618921.

It is not an unprimeable number, because it can be changed into a prime (1618931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4726 + ... + 5056.

It is an arithmetic number, because the mean of its divisors is an integer number (208828).

2^1618921 is an apocalyptic number.

It is an amenable number.

1618921 is a deficient number, since it is larger than the sum of its proper divisors (51703).

1618921 is an equidigital number, since it uses as much as digits as its factorization.

1618921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471.

The product of its digits is 864, while the sum is 28.

The square root of 1618921 is about 1272.3682643009. The cubic root of 1618921 is about 117.4199484921.

The spelling of 1618921 in words is "one million, six hundred eighteen thousand, nine hundred twenty-one".