1221312120431 has 16 divisors (see below), whose sum is σ = 1355649357888. Its totient is φ = 1093265510400.

The previous prime is 1221312120409. The next prime is 1221312120473. The reversal of 1221312120431 is 1340212131221.

It is a cyclic number.

It is not a de Polignac number, because 1221312120431 - 2³⁴ = 1204132251247 is a prime.

It is a super-2 number, since 2×1221312120431² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1221312120397 and 1221312120406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221312120631) 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, 10789586 + ... + 10902191.

It is an arithmetic number, because the mean of its divisors is an integer number (84728084868).

Almost surely, 2^{1221312120431} is an apocalyptic number.

1221312120431 is a deficient number, since it is larger than the sum of its proper divisors (134337237457).

1221312120431 is a wasteful number, since it uses less digits than its factorization.

1221312120431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21691922.

The product of its (nonzero) digits is 576, while the sum is 23.

Adding to 1221312120431 its reverse (1340212131221), we get a palindrome (2561524251652).

The spelling of 1221312120431 in words is "one trillion, two hundred twenty-one billion, three hundred twelve million, one hundred twenty thousand, four hundred thirty-one".