1211145540 has 96 divisors (see below), whose sum is σ = 3736333440. Its totient is φ = 290688000.

The previous prime is 1211145539. The next prime is 1211145563. The reversal of 1211145540 is 455411121.

It is a self number, because there is not a number n which added to its sum of digits gives 1211145540.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 57576 + ... + 75744.

It is an arithmetic number, because the mean of its divisors is an integer number (38920140).

Almost surely, 2^1211145540 is an apocalyptic number.

1211145540 is a gapful number since it is divisible by the number (10) 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 1211145540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1868166720).

1211145540 is an abundant number, since it is smaller than the sum of its proper divisors (2525187900).

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

1211145540 is a wasteful number, since it uses less digits than its factorization.

1211145540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18293 (or 18291 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 24.

The square root of 1211145540 is about 34801.5163462743. The cubic root of 1211145540 is about 1065.9384089343.

Adding to 1211145540 its reverse (455411121), we get a palindrome (1666556661).

The spelling of 1211145540 in words is "one billion, two hundred eleven million, one hundred forty-five thousand, five hundred forty".