1221012220021 has 8 divisors (see below), whose sum is σ = 1389926954304. Its totient is φ = 1061749756320.

The previous prime is 1221012220009. The next prime is 1221012220061. The reversal of 1221012220021 is 1200222101221.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1221012220021 - 2¹³ = 1221012211829 is a prime.

It is a super-2 number, since 2×1221012220021² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221012219977 and 1221012220004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221012220061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2413067376 + ... + 2413067881.

It is an arithmetic number, because the mean of its divisors is an integer number (173740869288).

Almost surely, 2^{1221012220021} is an apocalyptic number.

1221012220021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221012220021 is a deficient number, since it is larger than the sum of its proper divisors (168914734283).

1221012220021 is a wasteful number, since it uses less digits than its factorization.

1221012220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4826135291.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 1221012220021 its reverse (1200222101221), we get a palindrome (2421234321242).

The spelling of 1221012220021 in words is "one trillion, two hundred twenty-one billion, twelve million, two hundred twenty thousand, twenty-one".