1021204021 has 2 divisors, whose sum is σ = 1021204022. Its totient is φ = 1021204020.

The previous prime is 1021204003. The next prime is 1021204049. The reversal of 1021204021 is 1204021201.

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., 772006225 + 249197796 = 27785^2 + 15786^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021204021 - 2¹³ = 1021195829 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1021203992 and 1021204010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1021204061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510602010 + 510602011.

It is an arithmetic number, because the mean of its divisors is an integer number (510602011).

Almost surely, 2^1021204021 is an apocalyptic number.

It is an amenable number.

1021204021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021204021 is an equidigital number, since it uses as much as digits as its factorization.

1021204021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 1021204021 is about 31956.2829659521. The cubic root of 1021204021 is about 1007.0186305762.

Adding to 1021204021 its reverse (1204021201), we get a palindrome (2225225222).

The spelling of 1021204021 in words is "one billion, twenty-one million, two hundred four thousand, twenty-one".