1021121212221 has 24 divisors (see below), whose sum is σ = 1609119779904. Its totient is φ = 618830458560.

The previous prime is 1021121212213. The next prime is 1021121212249. The reversal of 1021121212221 is 1222121211201.

1021121212221 is a `hidden beast` number, since 1 + 0 + 211 + 21 + 212 + 221 = 666.

It is not a de Polignac number, because 1021121212221 - 2³ = 1021121212213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1021121212194 and 1021121212203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021121212121) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1820905 + ... + 2314721.

It is an arithmetic number, because the mean of its divisors is an integer number (67046657496).

Almost surely, 2^{1021121212221} is an apocalyptic number.

1021121212221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1021121212221 is a deficient number, since it is larger than the sum of its proper divisors (587998567683).

1021121212221 is a wasteful number, since it uses less digits than its factorization.

1021121212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 514721 (or 514718 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 1021121212221 its reverse (1222121211201), we get a palindrome (2243242423422).

The spelling of 1021121212221 in words is "one trillion, twenty-one billion, one hundred twenty-one million, two hundred twelve thousand, two hundred twenty-one".