1221012109979 has 2 divisors, whose sum is σ = 1221012109980. Its totient is φ = 1221012109978.

The previous prime is 1221012109973. The next prime is 1221012110023. The reversal of 1221012109979 is 9799012101221.

It is an a-pointer prime, because the next prime (1221012110023) can be obtained adding 1221012109979 to its sum of digits (44).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1221012109979 - 2²⁸ = 1220743674523 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221012109973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610506054989 + 610506054990.

It is an arithmetic number, because the mean of its divisors is an integer number (610506054990).

Almost surely, 2^{1221012109979} is an apocalyptic number.

1221012109979 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221012109979 is an equidigital number, since it uses as much as digits as its factorization.

1221012109979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40824, while the sum is 44.

The spelling of 1221012109979 in words is "one trillion, two hundred twenty-one billion, twelve million, one hundred nine thousand, nine hundred seventy-nine".