1211111220021 has 8 divisors (see below), whose sum is σ = 1615176800640. Its totient is φ = 807226559712.

The previous prime is 1211111219959. The next prime is 1211111220031. The reversal of 1211111220021 is 1200221111121.

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 1211111220021 - 2⁶ = 1211111219957 is a prime.

It is a super-4 number, since 4×1211111220021⁴ (a number of 49 digits) contains 4444 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211111220031) 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, 45214456 + ... + 45241233.

It is an arithmetic number, because the mean of its divisors is an integer number (201897100080).

Almost surely, 2^{1211111220021} is an apocalyptic number.

It is an amenable number.

1211111220021 is a deficient number, since it is larger than the sum of its proper divisors (404065580619).

1211111220021 is an equidigital number, since it uses as much as digits as its factorization.

1211111220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90460155.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 1211111220021 its reverse (1200221111121), we get a palindrome (2411332331142).

The spelling of 1211111220021 in words is "one trillion, two hundred eleven billion, one hundred eleven million, two hundred twenty thousand, twenty-one".