1021212121 has 4 divisors (see below), whose sum is σ = 1065612672. Its totient is φ = 976811572.

The previous prime is 1021212113. The next prime is 1021212131. The reversal of 1021212121 is 1212121201.

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: 1212121201 = 103 ⋅11768167.

It is a cyclic number.

It is not a de Polignac number, because 1021212121 - 2³ = 1021212113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1021212131) 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, 22200241 + ... + 22200286.

It is an arithmetic number, because the mean of its divisors is an integer number (266403168).

Almost surely, 2^1021212121 is an apocalyptic number.

It is an amenable number.

1021212121 is a deficient number, since it is larger than the sum of its proper divisors (44400551).

1021212121 is an equidigital number, since it uses as much as digits as its factorization.

1021212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44400550.

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 1021212121 is about 31956.4097013416. The cubic root of 1021212121 is about 1007.0212930638.

Adding to 1021212121 its reverse (1212121201), we get a palindrome (2233333322).

The spelling of 1021212121 in words is "one billion, twenty-one million, two hundred twelve thousand, one hundred twenty-one".