1221320433 has 16 divisors (see below), whose sum is σ = 1639638720. Its totient is φ = 808626624.

The previous prime is 1221320371. The next prime is 1221320449. The reversal of 1221320433 is 3340231221.

It is not a de Polignac number, because 1221320433 - 2⁹ = 1221319921 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221320453) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 302335 + ... + 306347.

It is an arithmetic number, because the mean of its divisors is an integer number (102477420).

Almost surely, 2^1221320433 is an apocalyptic number.

It is an amenable number.

1221320433 is a deficient number, since it is larger than the sum of its proper divisors (418318287).

1221320433 is a wasteful number, since it uses less digits than its factorization.

1221320433 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4688.

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 1221320433 is about 34947.3952248233. The cubic root of 1221320433 is about 1068.9150889464.

Adding to 1221320433 its reverse (3340231221), we get a palindrome (4561551654).

The spelling of 1221320433 in words is "one billion, two hundred twenty-one million, three hundred twenty thousand, four hundred thirty-three".