1221281173 has 32 divisors (see below), whose sum is σ = 1524531456. Its totient is φ = 954590208.

The previous prime is 1221281161. The next prime is 1221281203. The reversal of 1221281173 is 3711821221.

It is not a de Polignac number, because 1221281173 - 2¹⁷ = 1221150101 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221281143) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 522315 + ... + 524647.

It is an arithmetic number, because the mean of its divisors is an integer number (47641608).

Almost surely, 2^1221281173 is an apocalyptic number.

It is an amenable number.

1221281173 is a deficient number, since it is larger than the sum of its proper divisors (303250283).

1221281173 is a wasteful number, since it uses less digits than its factorization.

1221281173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2493.

The product of its digits is 1344, while the sum is 28.

The square root of 1221281173 is about 34946.8335189327. The cubic root of 1221281173 is about 1068.9036352075.

The spelling of 1221281173 in words is "one billion, two hundred twenty-one million, two hundred eighty-one thousand, one hundred seventy-three".