1221799679 has 2 divisors, whose sum is σ = 1221799680. Its totient is φ = 1221799678.

The previous prime is 1221799669. The next prime is 1221799729. The reversal of 1221799679 is 9769971221.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221799679 - 2¹² = 1221795583 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1221799679.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221799669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610899839 + 610899840.

It is an arithmetic number, because the mean of its divisors is an integer number (610899840).

Almost surely, 2^1221799679 is an apocalyptic number.

1221799679 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221799679 is an equidigital number, since it uses as much as digits as its factorization.

1221799679 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 857304, while the sum is 53.

The square root of 1221799679 is about 34954.2512292854. The cubic root of 1221799679 is about 1069.0548847161.

The spelling of 1221799679 in words is "one billion, two hundred twenty-one million, seven hundred ninety-nine thousand, six hundred seventy-nine".