1221378 has 8 divisors (see below), whose sum is σ = 2442768. Its totient is φ = 407124.

The previous prime is 1221373. The next prime is 1221379. The reversal of 1221378 is 8731221.

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

1221378 is an admirable number.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (1221373) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 101776 + ... + 101787.

It is an arithmetic number, because the mean of its divisors is an integer number (305346).

2^1221378 is an apocalyptic number.

1221378 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

1221378 is a wasteful number, since it uses less digits than its factorization.

1221378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203568.

The product of its digits is 672, while the sum is 24.

The square root of 1221378 is about 1105.1597169640. The cubic root of 1221378 is about 106.8931883138.

Adding to 1221378 its reverse (8731221), we get a palindrome (9952599).

The spelling of 1221378 in words is "one million, two hundred twenty-one thousand, three hundred seventy-eight".