1221012321 has 8 divisors (see below), whose sum is σ = 1672017024. Its totient is φ = 792007920.

The previous prime is 1221012319. The next prime is 1221012337. The reversal of 1221012321 is 1232101221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1221012321 - 2¹ = 1221012319 is a prime.

1221012321 is a modest number, since divided by 12321 gives 1221 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 1221012321.

It is not an unprimeable number, because it can be changed into a prime (1221012361) 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, 5499945 + ... + 5500166.

It is an arithmetic number, because the mean of its divisors is an integer number (209002128).

Almost surely, 2^1221012321 is an apocalyptic number.

It is an amenable number.

1221012321 is a deficient number, since it is larger than the sum of its proper divisors (451004703).

1221012321 is a wasteful number, since it uses less digits than its factorization.

1221012321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11000151.

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 1221012321 is about 34942.9867212292. The cubic root of 1221012321 is about 1068.8251935468.

Adding to 1221012321 its reverse (1232101221), we get a palindrome (2453113542).

Subtracting 1221012321 from its reverse (1232101221), we obtain a square (11088900 = 3330²).

It can be divided in two parts, 12210 and 12321, that added together give a triangular number (24531 = T₂₂₁).

The spelling of 1221012321 in words is "one billion, two hundred twenty-one million, twelve thousand, three hundred twenty-one".