1221778 has 8 divisors (see below), whose sum is σ = 1840572. Its totient is φ = 608256.

The previous prime is 1221767. The next prime is 1221791. The reversal of 1221778 is 8771221.

It can be written as a sum of positive squares in 2 ways, for example, as 1129969 + 91809 = 1063^2 + 303^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 675 + ... + 1702.

2^1221778 is an apocalyptic number.

1221778 is a deficient number, since it is larger than the sum of its proper divisors (618794).

1221778 is a wasteful number, since it uses less digits than its factorization.

1221778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2636.

The product of its digits is 1568, while the sum is 28.

The square root of 1221778 is about 1105.3406714674. The cubic root of 1221778 is about 106.9048561754.

Adding to 1221778 its reverse (8771221), we get a palindrome (9992999).

The spelling of 1221778 in words is "one million, two hundred twenty-one thousand, seven hundred seventy-eight".