1221001211231 has 2 divisors, whose sum is σ = 1221001211232. Its totient is φ = 1221001211230.

The previous prime is 1221001211191. The next prime is 1221001211263. The reversal of 1221001211231 is 1321121001221.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221001211231 is a prime.

It is a super-2 number, since 2×1221001211231² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221001214231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610500605615 + 610500605616.

It is an arithmetic number, because the mean of its divisors is an integer number (610500605616).

Almost surely, 2^{1221001211231} is an apocalyptic number.

1221001211231 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221001211231 is an equidigital number, since it uses as much as digits as its factorization.

1221001211231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 1221001211231 its reverse (1321121001221), we get a palindrome (2542122212452).

It can be divided in two parts, 122100 and 1211231, that added together give a palindrome (1333331).

The spelling of 1221001211231 in words is "one trillion, two hundred twenty-one billion, one million, two hundred eleven thousand, two hundred thirty-one".