355121021 has 2 divisors, whose sum is σ = 355121022. Its totient is φ = 355121020.

The previous prime is 355120999. The next prime is 355121057. The reversal of 355121021 is 120121553.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 341140900 + 13980121 = 18470^2 + 3739^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-355121021 is a prime.

It is a super-2 number, since 2×355121021² = 252221879112164882, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 355120984 and 355121002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (355121071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 177560510 + 177560511.

It is an arithmetic number, because the mean of its divisors is an integer number (177560511).

Almost surely, 2^355121021 is an apocalyptic number.

It is an amenable number.

355121021 is a deficient number, since it is larger than the sum of its proper divisors (1).

355121021 is an equidigital number, since it uses as much as digits as its factorization.

355121021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 300, while the sum is 20.

The square root of 355121021 is about 18844.6549716359. The cubic root of 355121021 is about 708.1503273045.

Adding to 355121021 its reverse (120121553), we get a palindrome (475242574).

The spelling of 355121021 in words is "three hundred fifty-five million, one hundred twenty-one thousand, twenty-one".