1220661 has 12 divisors (see below), whose sum is σ = 1898988. Its totient is φ = 751104.

The previous prime is 1220657. The next prime is 1220663. The reversal of 1220661 is 1660221.

It is a happy number.

1220661 is a `hidden beast` number, since 1 + 2 + 2 + 0 + 661 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 463761 + 756900 = 681^2 + 870^2 .

It is not a de Polignac number, because 1220661 - 2² = 1220657 is a prime.

It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220663) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5100 + ... + 5333.

It is an arithmetic number, because the mean of its divisors is an integer number (158249).

2^1220661 is an apocalyptic number.

It is an amenable number.

1220661 is a deficient number, since it is larger than the sum of its proper divisors (678327).

1220661 is a wasteful number, since it uses less digits than its factorization.

1220661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10452 (or 10449 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 1220661 is about 1104.8352818407. The cubic root of 1220661 is about 106.8722672944.

Adding to 1220661 its reverse (1660221), we get a palindrome (2880882).

It can be divided in two parts, 1220 and 661, that added together give a palindrome (1881).

The spelling of 1220661 in words is "one million, two hundred twenty thousand, six hundred sixty-one".