1221115021 has 8 divisors (see below), whose sum is σ = 1401551424. Its totient is φ = 1042176480.

The previous prime is 1221114949. The next prime is 1221115043. The reversal of 1221115021 is 1205111221.

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

It is a cyclic number.

It is not a de Polignac number, because 1221115021 - 2¹³ = 1221106829 is a prime.

It is a super-2 number, since 2×1221115021² = 2982243789023660882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1221114986 and 1221115004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221115081) 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, 372715 + ... + 375976.

It is an arithmetic number, because the mean of its divisors is an integer number (175193928).

Almost surely, 2^1221115021 is an apocalyptic number.

It is an amenable number.

1221115021 is a deficient number, since it is larger than the sum of its proper divisors (180436403).

1221115021 is an equidigital number, since it uses as much as digits as its factorization.

1221115021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 748931.

The product of its (nonzero) digits is 40, while the sum is 16.

The square root of 1221115021 is about 34944.4562269897. The cubic root of 1221115021 is about 1068.8551591931.

Adding to 1221115021 its reverse (1205111221), we get a palindrome (2426226242).

The spelling of 1221115021 in words is "one billion, two hundred twenty-one million, one hundred fifteen thousand, twenty-one".