1918221 has 16 divisors (see below), whose sum is σ = 2735040. Its totient is φ = 1192320.

The previous prime is 1918219. The next prime is 1918237. The reversal of 1918221 is 1228191.

It is not a de Polignac number, because 1918221 - 2¹ = 1918219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1918191 and 1918200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1918121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3931 + ... + 4391.

It is an arithmetic number, because the mean of its divisors is an integer number (170940).

2^1918221 is an apocalyptic number.

It is an amenable number.

1918221 is a deficient number, since it is larger than the sum of its proper divisors (816819).

1918221 is a wasteful number, since it uses less digits than its factorization.

1918221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 556.

The product of its digits is 288, while the sum is 24.

The square root of 1918221 is about 1384.9985559559. The cubic root of 1918221 is about 124.2509011077.

The spelling of 1918221 in words is "one million, nine hundred eighteen thousand, two hundred twenty-one".