1221035021 has 2 divisors, whose sum is σ = 1221035022. Its totient is φ = 1221035020.

The previous prime is 1221034973. The next prime is 1221035059. The reversal of 1221035021 is 1205301221.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1010349796 + 210685225 = 31786^2 + 14515^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221035021 - 2²⁶ = 1153926157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221035521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610517510 + 610517511.

It is an arithmetic number, because the mean of its divisors is an integer number (610517511).

Almost surely, 2^1221035021 is an apocalyptic number.

It is an amenable number.

1221035021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221035021 is an equidigital number, since it uses as much as digits as its factorization.

1221035021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 1221035021 is about 34943.3115345412. The cubic root of 1221035021 is about 1068.8318170621.

Adding to 1221035021 its reverse (1205301221), we get a palindrome (2426336242).

The spelling of 1221035021 in words is "one billion, two hundred twenty-one million, thirty-five thousand, twenty-one".