1213223521 has 4 divisors (see below), whose sum is σ = 1214592192. Its totient is φ = 1211854852.

The previous prime is 1213223509. The next prime is 1213223537. The reversal of 1213223521 is 1253223121.

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.

It is a cyclic number.

It is not a de Polignac number, because 1213223521 - 2¹³ = 1213215329 is a prime.

It is a super-2 number, since 2×1213223521² = 2943822623815274882, 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 = 1213223492 and 1213223501.

It is not an unprimeable number, because it can be changed into a prime (1213223551) 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, 683005 + ... + 684778.

It is an arithmetic number, because the mean of its divisors is an integer number (303648048).

Almost surely, 2^1213223521 is an apocalyptic number.

It is an amenable number.

1213223521 is a deficient number, since it is larger than the sum of its proper divisors (1368671).

1213223521 is an equidigital number, since it uses as much as digits as its factorization.

1213223521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1368670.

The product of its digits is 720, while the sum is 22.

The square root of 1213223521 is about 34831.3582996701. The cubic root of 1213223521 is about 1066.5476762558.

Adding to 1213223521 its reverse (1253223121), we get a palindrome (2466446642).

It can be divided in two parts, 12132 and 23521, that added together give a palindrome (35653).

The spelling of 1213223521 in words is "one billion, two hundred thirteen million, two hundred twenty-three thousand, five hundred twenty-one".