212121220021001 has 4 divisors (see below), whose sum is σ = 212128938880404. Its totient is φ = 212113501161600.

The previous prime is 212121220020979. The next prime is 212121220021013. The reversal of 212121220021001 is 100120022121212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 208410337907776 + 3710882113225 = 14436424^2 + 1926365^2 .

It is a cyclic number.

It is not a de Polignac number, because 212121220021001 - 2⁴² = 207723173509897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (232121220021001) 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, 3859388480 + ... + 3859443441.

It is an arithmetic number, because the mean of its divisors is an integer number (53032234720101).

Almost surely, 2^{212121220021001} is an apocalyptic number.

It is an amenable number.

212121220021001 is a deficient number, since it is larger than the sum of its proper divisors (7718859403).

212121220021001 is an equidigital number, since it uses as much as digits as its factorization.

212121220021001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7718859402.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 212121220021001 its reverse (100120022121212), we get a palindrome (312241242142213).

The spelling of 212121220021001 in words is "two hundred twelve trillion, one hundred twenty-one billion, two hundred twenty million, twenty-one thousand, one".