1221993673 has 2 divisors, whose sum is σ = 1221993674. Its totient is φ = 1221993672.

The previous prime is 1221993671. The next prime is 1221993697. The reversal of 1221993673 is 3763991221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 930677049 + 291316624 = 30507^2 + 17068^2 .

It is an emirp because it is prime and its reverse (3763991221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221993673 - 2¹ = 1221993671 is a prime.

Together with 1221993671, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1221993671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610996836 + 610996837.

It is an arithmetic number, because the mean of its divisors is an integer number (610996837).

Almost surely, 2^1221993673 is an apocalyptic number.

It is an amenable number.

1221993673 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221993673 is an equidigital number, since it uses as much as digits as its factorization.

1221993673 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 122472, while the sum is 43.

The square root of 1221993673 is about 34957.0260891856. The cubic root of 1221993673 is about 1069.1114622554. Note that the first 3 decimals are identical.

The spelling of 1221993673 in words is "one billion, two hundred twenty-one million, nine hundred ninety-three thousand, six hundred seventy-three".