1321222661 has 16 divisors (see below), whose sum is σ = 1454906880. Its totient is φ = 1189841520.

The previous prime is 1321222633. The next prime is 1321222673. The reversal of 1321222661 is 1662221231.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1321222661 - 2¹⁴ = 1321206277 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1321222661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321222621) 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, 1135466 + ... + 1136628.

It is an arithmetic number, because the mean of its divisors is an integer number (90931680).

Almost surely, 2^1321222661 is an apocalyptic number.

1321222661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1321222661 is a deficient number, since it is larger than the sum of its proper divisors (133684219).

1321222661 is a wasteful number, since it uses less digits than its factorization.

1321222661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2056.

The product of its digits is 1728, while the sum is 26.

The square root of 1321222661 is about 36348.6266728194. The cubic root of 1321222661 is about 1097.2998958206.

Adding to 1321222661 its reverse (1662221231), we get a palindrome (2983443892).

The spelling of 1321222661 in words is "one billion, three hundred twenty-one million, two hundred twenty-two thousand, six hundred sixty-one".