1211521650 has 24 divisors (see below), whose sum is σ = 3004574064. Its totient is φ = 323072400.

The previous prime is 1211521639. The next prime is 1211521693. The reversal of 1211521650 is 561251121.

It is a self number, because there is not a number n which added to its sum of digits gives 1211521650.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4038256 + ... + 4038555.

It is an arithmetic number, because the mean of its divisors is an integer number (125190586).

Almost surely, 2^1211521650 is an apocalyptic number.

1211521650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1211521650 is an abundant number, since it is smaller than the sum of its proper divisors (1793052414).

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

1211521650 is a wasteful number, since it uses less digits than its factorization.

1211521650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8076826 (or 8076821 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 24.

The square root of 1211521650 is about 34806.9195706831. The cubic root of 1211521650 is about 1066.0487366060.

Adding to 1211521650 its reverse (561251121), we get a palindrome (1772772771).

The spelling of 1211521650 in words is "one billion, two hundred eleven million, five hundred twenty-one thousand, six hundred fifty".