1221002111311 has 4 divisors (see below), whose sum is σ = 1260389276224. Its totient is φ = 1181614946400.

The previous prime is 1221002111309. The next prime is 1221002111447. The reversal of 1221002111311 is 1131112001221.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1221002111311 - 2¹ = 1221002111309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221002141311) 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, 19693582410 + ... + 19693582471.

It is an arithmetic number, because the mean of its divisors is an integer number (315097319056).

Almost surely, 2^{1221002111311} is an apocalyptic number.

1221002111311 is a deficient number, since it is larger than the sum of its proper divisors (39387164913).

1221002111311 is an equidigital number, since it uses as much as digits as its factorization.

1221002111311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39387164912.

The product of its (nonzero) digits is 24, while the sum is 16.

Adding to 1221002111311 its reverse (1131112001221), we get a palindrome (2352114112532).

The spelling of 1221002111311 in words is "one trillion, two hundred twenty-one billion, two million, one hundred eleven thousand, three hundred eleven".