1221053531 has 8 divisors (see below), whose sum is σ = 1241651184. Its totient is φ = 1200474720.

The previous prime is 1221053521. The next prime is 1221053573. The reversal of 1221053531 is 1353501221.

It is a happy number.

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 1221053531 - 2¹⁰ = 1221052507 is a prime.

It is a super-2 number, since 2×1221053531² = 2981943451135135922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221053497 and 1221053506.

It is not an unprimeable number, because it can be changed into a prime (1221053501) 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, 198701 + ... + 204753.

It is an arithmetic number, because the mean of its divisors is an integer number (155206398).

Almost surely, 2^1221053531 is an apocalyptic number.

1221053531 is a deficient number, since it is larger than the sum of its proper divisors (20597653).

1221053531 is an equidigital number, since it uses as much as digits as its factorization.

1221053531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9421.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 1221053531 is about 34943.5763910908. The cubic root of 1221053531 is about 1068.8372179383.

Adding to 1221053531 its reverse (1353501221), we get a palindrome (2574554752).

The spelling of 1221053531 in words is "one billion, two hundred twenty-one million, fifty-three thousand, five hundred thirty-one".