1221223541 has 4 divisors (see below), whose sum is σ = 1221946572. Its totient is φ = 1220500512.

The previous prime is 1221223529. The next prime is 1221223561. The reversal of 1221223541 is 1453221221.

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

It can be written as a sum of positive squares in 2 ways, for example, as 466128100 + 755095441 = 21590^2 + 27479^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221223541 - 2¹⁸ = 1220961397 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221223511) 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, 358976 + ... + 362361.

It is an arithmetic number, because the mean of its divisors is an integer number (305486643).

Almost surely, 2^1221223541 is an apocalyptic number.

It is an amenable number.

1221223541 is a deficient number, since it is larger than the sum of its proper divisors (723031).

1221223541 is an equidigital number, since it uses as much as digits as its factorization.

1221223541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 723030.

The product of its digits is 960, while the sum is 23.

The square root of 1221223541 is about 34946.0089423671. The cubic root of 1221223541 is about 1068.8868211643.

Adding to 1221223541 its reverse (1453221221), we get a palindrome (2674444762).

It can be divided in two parts, 12212 and 23541, that added together give a palindrome (35753).

The spelling of 1221223541 in words is "one billion, two hundred twenty-one million, two hundred twenty-three thousand, five hundred forty-one".