1221404134243 has 4 divisors (see below), whose sum is σ = 1221442059448. Its totient is φ = 1221366209040.

The previous prime is 1221404134207. The next prime is 1221404134277. The reversal of 1221404134243 is 3424314041221.

It is a happy number.

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 1221404134243 - 2¹³ = 1221404126051 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221404134943) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18914253 + ... + 18978718.

It is an arithmetic number, because the mean of its divisors is an integer number (305360514862).

Almost surely, 2^{1221404134243} is an apocalyptic number.

1221404134243 is a deficient number, since it is larger than the sum of its proper divisors (37925205).

1221404134243 is an equidigital number, since it uses as much as digits as its factorization.

1221404134243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37925204.

The product of its (nonzero) digits is 18432, while the sum is 31.

Adding to 1221404134243 its reverse (3424314041221), we get a palindrome (4645718175464).

The spelling of 1221404134243 in words is "one trillion, two hundred twenty-one billion, four hundred four million, one hundred thirty-four thousand, two hundred forty-three".