1221212013231 has 16 divisors (see below), whose sum is σ = 1860910271744. Its totient is φ = 697829520384.

The previous prime is 1221212013173. The next prime is 1221212013317. The reversal of 1221212013231 is 1323102121221.

It is not a de Polignac number, because 1221212013231 - 2⁷ = 1221212013103 is a prime.

It is a super-2 number, since 2×1221212013231² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221212013198 and 1221212013207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221212013031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3955836 + ... + 4253358.

It is an arithmetic number, because the mean of its divisors is an integer number (116306891984).

Almost surely, 2^{1221212013231} is an apocalyptic number.

1221212013231 is a deficient number, since it is larger than the sum of its proper divisors (639698258513).

1221212013231 is a wasteful number, since it uses less digits than its factorization.

1221212013231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492990.

The product of its (nonzero) digits is 288, while the sum is 21.

Adding to 1221212013231 its reverse (1323102121221), we get a palindrome (2544314134452).

The spelling of 1221212013231 in words is "one trillion, two hundred twenty-one billion, two hundred twelve million, thirteen thousand, two hundred thirty-one".