1221861943 has 4 divisors (see below), whose sum is σ = 1233959688. Its totient is φ = 1209764200.

The previous prime is 1221861941. The next prime is 1221861967. The reversal of 1221861943 is 3491681221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221861943 - 2¹ = 1221861941 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221861941) 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 in 3 ways as a sum of consecutive naturals, for example, 6048721 + ... + 6048922.

It is an arithmetic number, because the mean of its divisors is an integer number (308489922).

Almost surely, 2^1221861943 is an apocalyptic number.

1221861943 is a deficient number, since it is larger than the sum of its proper divisors (12097745).

1221861943 is a wasteful number, since it uses less digits than its factorization.

1221861943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12097744.

The product of its digits is 20736, while the sum is 37.

The square root of 1221861943 is about 34955.1418678283. The cubic root of 1221861943 is about 1069.0730444041.

The spelling of 1221861943 in words is "one billion, two hundred twenty-one million, eight hundred sixty-one thousand, nine hundred forty-three".