1242021021 has 4 divisors (see below), whose sum is σ = 1656028032. Its totient is φ = 828014012.

The previous prime is 1242021007. The next prime is 1242021029. The reversal of 1242021021 is 1201202421.

1242021021 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1201202421 = 3 ⋅400400807.

It is a cyclic number.

It is not a de Polignac number, because 1242021021 - 2¹⁰ = 1242019997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1242021029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 207003501 + ... + 207003506.

It is an arithmetic number, because the mean of its divisors is an integer number (414007008).

Almost surely, 2^1242021021 is an apocalyptic number.

It is an amenable number.

1242021021 is a deficient number, since it is larger than the sum of its proper divisors (414007011).

1242021021 is an equidigital number, since it uses as much as digits as its factorization.

1242021021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414007010.

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 1242021021 is about 35242.3186098758. The cubic root of 1242021021 is about 1074.9204256224.

Adding to 1242021021 its reverse (1201202421), we get a palindrome (2443223442).

The spelling of 1242021021 in words is "one billion, two hundred forty-two million, twenty-one thousand, twenty-one".