1225529820 has 72 divisors (see below), whose sum is σ = 3837375360. Its totient is φ = 316264320.

The previous prime is 1225529803. The next prime is 1225529827. The reversal of 1225529820 is 289255221.

1225529820 is a `hidden beast` number, since 1 + 22 + 552 + 9 + 82 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1225529827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 104235 + ... + 115394.

It is an arithmetic number, because the mean of its divisors is an integer number (53296880).

Almost surely, 2^1225529820 is an apocalyptic number.

1225529820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1225529820 is an abundant number, since it is smaller than the sum of its proper divisors (2611845540).

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

1225529820 is a wasteful number, since it uses less digits than its factorization.

1225529820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219675 (or 219670 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 1225529820 is about 35007.5680389255. The cubic root of 1225529820 is about 1070.1417170432.

The spelling of 1225529820 in words is "one billion, two hundred twenty-five million, five hundred twenty-nine thousand, eight hundred twenty".