1221234021 has 12 divisors (see below), whose sum is σ = 2016005472. Its totient is φ = 697847976.

The previous prime is 1221234011. The next prime is 1221234037. The reversal of 1221234021 is 1204321221.

It is a happy number.

It is not a de Polignac number, because 1221234021 - 2⁵ = 1221233989 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221233985 and 1221234003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221234011) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9692271 + ... + 9692396.

It is an arithmetic number, because the mean of its divisors is an integer number (168000456).

Almost surely, 2^1221234021 is an apocalyptic number.

It is an amenable number.

1221234021 is a deficient number, since it is larger than the sum of its proper divisors (794771451).

1221234021 is a wasteful number, since it uses less digits than its factorization.

1221234021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19384680 (or 19384677 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 1221234021 is about 34946.1588876374. The cubic root of 1221234021 is about 1068.8898787268.

Adding to 1221234021 its reverse (1204321221), we get a palindrome (2425555242).

The spelling of 1221234021 in words is "one billion, two hundred twenty-one million, two hundred thirty-four thousand, twenty-one".