1216155653325 has 108 divisors (see below), whose sum is σ = 2264548134420. Its totient is φ = 647867082240.

The previous prime is 1216155653311. The next prime is 1216155653327. The reversal of 1216155653325 is 5233565516121.

1216155653325 is a `hidden beast` number, since 1 + 2 + 1 + 61 + 5 + 56 + 533 + 2 + 5 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 54532991529 + 1161622661796 = 233523^2 + 1077786^2 .

It is not a de Polignac number, because 1216155653325 - 2⁷ = 1216155653197 is a prime.

It is a super-2 number, since 2×1216155653325² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216155653327) by changing a digit.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 160248631 + ... + 160256219.

Almost surely, 2^{1216155653325} is an apocalyptic number.

1216155653325 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1216155653325 is a deficient number, since it is larger than the sum of its proper divisors (1048392481095).

1216155653325 is an frugal number, since it uses more digits than its factorization.

1216155653325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8600 (or 8574 counting only the distinct ones).

The product of its digits is 810000, while the sum is 45.

The spelling of 1216155653325 in words is "one trillion, two hundred sixteen billion, one hundred fifty-five million, six hundred fifty-three thousand, three hundred twenty-five".