1221398143 has 16 divisors (see below), whose sum is σ = 1408458240. Its totient is φ = 1037510496.

The previous prime is 1221398131. The next prime is 1221398179. The reversal of 1221398143 is 3418931221.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1221398143 - 2⁵ = 1221398111 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221398099 and 1221398108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221398443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 955821 + ... + 957097.

It is an arithmetic number, because the mean of its divisors is an integer number (88028640).

Almost surely, 2^1221398143 is an apocalyptic number.

1221398143 is a deficient number, since it is larger than the sum of its proper divisors (187060097).

1221398143 is a wasteful number, since it uses less digits than its factorization.

1221398143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2406.

The product of its digits is 10368, while the sum is 34.

The square root of 1221398143 is about 34948.5070210445. The cubic root of 1221398143 is about 1068.9377593905.

The spelling of 1221398143 in words is "one billion, two hundred twenty-one million, three hundred ninety-eight thousand, one hundred forty-three".