231321441655621 has 16 divisors (see below), whose sum is σ = 251632294990848. Its totient is φ = 212006375856000.

The previous prime is 231321441655573. The next prime is 231321441655669. The reversal of 231321441655621 is 126556144123132.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (231321441655573) and next prime (231321441655669).

It is a cyclic number.

It is not a de Polignac number, because 231321441655621 - 2¹¹ = 231321441653573 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 (231321441655321) 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, 1606036896 + ... + 1606180921.

It is an arithmetic number, because the mean of its divisors is an integer number (15727018436928).

Almost surely, 2^{231321441655621} is an apocalyptic number.

It is an amenable number.

231321441655621 is a deficient number, since it is larger than the sum of its proper divisors (20310853335227).

231321441655621 is a wasteful number, since it uses less digits than its factorization.

231321441655621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3212217972.

The product of its digits is 1036800, while the sum is 46.

Adding to 231321441655621 its reverse (126556144123132), we get a palindrome (357877585778753).

The spelling of 231321441655621 in words is "two hundred thirty-one trillion, three hundred twenty-one billion, four hundred forty-one million, six hundred fifty-five thousand, six hundred twenty-one".