1220298661 has 4 divisors (see below), whose sum is σ = 1221644992. Its totient is φ = 1218952332.

The previous prime is 1220298631. The next prime is 1220298683. The reversal of 1220298661 is 1668920221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1668920221 = 257 ⋅6493853.

It is a cyclic number.

It is not a de Polignac number, because 1220298661 - 2¹⁹ = 1219774373 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 1220298661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220298631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 671805 + ... + 673618.

It is an arithmetic number, because the mean of its divisors is an integer number (305411248).

Almost surely, 2^1220298661 is an apocalyptic number.

It is an amenable number.

1220298661 is a deficient number, since it is larger than the sum of its proper divisors (1346331).

1220298661 is an equidigital number, since it uses as much as digits as its factorization.

1220298661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1346330.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 1220298661 is about 34932.7734513021. The cubic root of 1220298661 is about 1068.6169165205.

The spelling of 1220298661 in words is "one billion, two hundred twenty million, two hundred ninety-eight thousand, six hundred sixty-one".