1221777 has 16 divisors (see below), whose sum is σ = 1860480. Its totient is φ = 791856.

The previous prime is 1221767. The next prime is 1221791. The reversal of 1221777 is 7771221.

It is not a de Polignac number, because 1221777 - 2⁴ = 1221761 is a prime.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 1221777.

It is not an unprimeable number, because it can be changed into a prime (1221707) 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, 388 + ... + 1610.

It is an arithmetic number, because the mean of its divisors is an integer number (116280).

2^1221777 is an apocalyptic number.

It is an amenable number.

1221777 is a deficient number, since it is larger than the sum of its proper divisors (638703).

1221777 is a wasteful number, since it uses less digits than its factorization.

1221777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1269 (or 1263 counting only the distinct ones).

The product of its digits is 1372, while the sum is 27.

The square root of 1221777 is about 1105.3402191181. The cubic root of 1221777 is about 106.9048270090.

Adding to 1221777 its reverse (7771221), we get a palindrome (8992998).

The spelling of 1221777 in words is "one million, two hundred twenty-one thousand, seven hundred seventy-seven".