1211165536 has 72 divisors (see below), whose sum is σ = 2863377216. Its totient is φ = 502306560.

The previous prime is 1211165521. The next prime is 1211165539. The reversal of 1211165536 is 6355611121.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a junction number, because it is equal to n+sod(n) for n = 1211165498 and 1211165507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211165539) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 36150 + ... + 61066.

It is an arithmetic number, because the mean of its divisors is an integer number (39769128).

Almost surely, 2^1211165536 is an apocalyptic number.

1211165536 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1211165536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1431688608).

1211165536 is an abundant number, since it is smaller than the sum of its proper divisors (1652211680).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1211165536 is a wasteful number, since it uses less digits than its factorization.

1211165536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24972 (or 24957 counting only the distinct ones).

The product of its digits is 5400, while the sum is 31.

The square root of 1211165536 is about 34801.8036314212. The cubic root of 1211165536 is about 1065.9442751126.

Adding to 1211165536 its reverse (6355611121), we get a palindrome (7566776657).

The spelling of 1211165536 in words is "one billion, two hundred eleven million, one hundred sixty-five thousand, five hundred thirty-six".