1216638 has 24 divisors (see below), whose sum is σ = 2656368. Its totient is φ = 402432.

The previous prime is 1216619. The next prime is 1216681. The reversal of 1216638 is 8366121.

1216638 is a `hidden beast` number, since 1 + 21 + 6 + 638 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4495 + ... + 4757.

It is an arithmetic number, because the mean of its divisors is an integer number (110682).

2^1216638 is an apocalyptic number.

1216638 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1216638 is an abundant number, since it is smaller than the sum of its proper divisors (1439730).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1216638 is a wasteful number, since it uses less digits than its factorization.

1216638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528 (or 525 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 1216638 is about 1103.0131458872. The cubic root of 1216638 is about 106.7547297932.

The spelling of 1216638 in words is "one million, two hundred sixteen thousand, six hundred thirty-eight".