1221123021 has 8 divisors (see below), whose sum is σ = 1658884320. Its totient is φ = 798721872.

The previous prime is 1221122999. The next prime is 1221123023. The reversal of 1221123021 is 1203211221.

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

It is not a de Polignac number, because 1221123021 - 2¹⁴ = 1221106637 is a prime.

It is a super-2 number, since 2×1221123021² = 2982282864832332882, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221123023) 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, 3839851 + ... + 3840168.

It is an arithmetic number, because the mean of its divisors is an integer number (207360540).

Almost surely, 2^1221123021 is an apocalyptic number.

It is an amenable number.

1221123021 is a deficient number, since it is larger than the sum of its proper divisors (437761299).

1221123021 is an equidigital number, since it uses as much as digits as its factorization.

1221123021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7680075.

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

The square root of 1221123021 is about 34944.5706941722. The cubic root of 1221123021 is about 1068.8574933501.

Adding to 1221123021 its reverse (1203211221), we get a palindrome (2424334242).

The spelling of 1221123021 in words is "one billion, two hundred twenty-one million, one hundred twenty-three thousand, twenty-one".