1221311541 has 8 divisors (see below), whose sum is σ = 1651351104. Its totient is φ = 802739840.

The previous prime is 1221311521. The next prime is 1221311543. The reversal of 1221311541 is 1451131221.

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

It is a cyclic number.

It is not a de Polignac number, because 1221311541 - 2¹⁴ = 1221295157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221311543) 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, 2866716 + ... + 2867141.

It is an arithmetic number, because the mean of its divisors is an integer number (206418888).

Almost surely, 2^1221311541 is an apocalyptic number.

It is an amenable number.

1221311541 is a deficient number, since it is larger than the sum of its proper divisors (430039563).

1221311541 is an equidigital number, since it uses as much as digits as its factorization.

1221311541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5733931.

The product of its digits is 240, while the sum is 21.

The square root of 1221311541 is about 34947.2680048098. The cubic root of 1221311541 is about 1068.9124948098.

Adding to 1221311541 its reverse (1451131221), we get a palindrome (2672442762).

The spelling of 1221311541 in words is "one billion, two hundred twenty-one million, three hundred eleven thousand, five hundred forty-one".