1216637678169 has 15 divisors (see below), whose sum is σ = 1817461237647. Its totient is φ = 811085167368.

The previous prime is 1216637678147. The next prime is 1216637678177. The reversal of 1216637678169 is 9618767366121.

The square root of 1216637678169 is 1103013.

It is a perfect power (a square), and thus also a powerful number.

1216637678169 is a `hidden beast` number, since 121 + 6 + 6 + 376 + 7 + 81 + 69 = 666.

It can be written as a sum of positive squares in only one way, i.e., 755308737225 + 461328940944 = 869085^2 + 679212^2 .

It is not a de Polignac number, because 1216637678169 - 2¹⁹ = 1216637153881 is a prime.

It is a super-2 number, since 2×1216637678169² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1216637678129) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 9865839 + ... + 9988395.

Almost surely, 2^{1216637678169} is an apocalyptic number.

1216637678169 is the 1103013-rd square number.

1216637678169 is the 551507-th centered octagonal number.

It is an amenable number.

1216637678169 is a deficient number, since it is larger than the sum of its proper divisors (600823559478).

1216637678169 is an frugal number, since it uses more digits than its factorization.

1216637678169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245126 (or 122560 counting only the distinct ones).

The product of its digits is 27433728, while the sum is 63.

The spelling of 1216637678169 in words is "one trillion, two hundred sixteen billion, six hundred thirty-seven million, six hundred seventy-eight thousand, one hundred sixty-nine".