1211225820 has 96 divisors (see below), whose sum is σ = 3880547328. Its totient is φ = 276521472.

The previous prime is 1211225773. The next prime is 1211225857. The reversal of 1211225820 is 285221121.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 606744 + ... + 608736.

It is an arithmetic number, because the mean of its divisors is an integer number (40422368).

Almost surely, 2^1211225820 is an apocalyptic number.

1211225820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1211225820 is an abundant number, since it is smaller than the sum of its proper divisors (2669321508).

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

1211225820 is a wasteful number, since it uses less digits than its factorization.

1211225820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3459 (or 3457 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 1211225820 is about 34802.6697251806. The cubic root of 1211225820 is about 1065.9619600936.

Adding to 1211225820 its reverse (285221121), we get a palindrome (1496446941).

The spelling of 1211225820 in words is "one billion, two hundred eleven million, two hundred twenty-five thousand, eight hundred twenty".