12221553 has 4 divisors (see below), whose sum is σ = 16295408. Its totient is φ = 8147700.

The previous prime is 12221543. The next prime is 12221593. The reversal of 12221553 is 35512221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 35512221 = 3 ⋅11837407.

It is not a de Polignac number, because 12221553 - 2¹⁰ = 12220529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12221543) 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, 2036923 + ... + 2036928.

It is an arithmetic number, because the mean of its divisors is an integer number (4073852).

Almost surely, 2^12221553 is an apocalyptic number.

It is an amenable number.

12221553 is a deficient number, since it is larger than the sum of its proper divisors (4073855).

12221553 is an equidigital number, since it uses as much as digits as its factorization.

12221553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4073854.

The product of its digits is 600, while the sum is 21.

The square root of 12221553 is about 3495.9337808374. The cubic root of 12221553 is about 230.3432367338.

Adding to 12221553 its reverse (35512221), we get a palindrome (47733774).

It can be divided in two parts, 1222 and 1553, that added together give a triangular number (2775 = T₇₄).

The spelling of 12221553 in words is "twelve million, two hundred twenty-one thousand, five hundred fifty-three".