1221961173 has 8 divisors (see below), whose sum is σ = 1725121728. Its totient is φ = 766720704.

The previous prime is 1221961129. The next prime is 1221961183. The reversal of 1221961173 is 3711691221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1221961173 - 2⁸ = 1221960917 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221961123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11979961 + ... + 11980062.

It is an arithmetic number, because the mean of its divisors is an integer number (215640216).

Almost surely, 2^1221961173 is an apocalyptic number.

It is an amenable number.

1221961173 is a deficient number, since it is larger than the sum of its proper divisors (503160555).

1221961173 is a wasteful number, since it uses less digits than its factorization.

1221961173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23960043.

The product of its digits is 4536, while the sum is 33.

The square root of 1221961173 is about 34956.5612296175. The cubic root of 1221961173 is about 1069.1019841838.

The spelling of 1221961173 in words is "one billion, two hundred twenty-one million, nine hundred sixty-one thousand, one hundred seventy-three".