1215551555231 has 4 divisors (see below), whose sum is σ = 1309055521032. Its totient is φ = 1122047589432.

The previous prime is 1215551555189. The next prime is 1215551555287. The reversal of 1215551555231 is 1325551555121.

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 1215551555231 - 2¹⁰ = 1215551554207 is a prime.

It is a super-2 number, since 2×1215551555231² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1215551555731) 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, 46751982881 + ... + 46751982906.

It is an arithmetic number, because the mean of its divisors is an integer number (327263880258).

Almost surely, 2^{1215551555231} is an apocalyptic number.

1215551555231 is a deficient number, since it is larger than the sum of its proper divisors (93503965801).

1215551555231 is an equidigital number, since it uses as much as digits as its factorization.

1215551555231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93503965800.

The product of its digits is 187500, while the sum is 41.

The spelling of 1215551555231 in words is "one trillion, two hundred fifteen billion, five hundred fifty-one million, five hundred fifty-five thousand, two hundred thirty-one".