1225635840 has 768 divisors, whose sum is σ = 5283532800. Its totient is φ = 265420800.

The previous prime is 1225635781. The next prime is 1225635847. The reversal of 1225635840 is 485365221.

1225635840 is a `hidden beast` number, since 1 + 2 + 2 + 563 + 58 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (768).

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

It is a junction number, because it is equal to n+sod(n) for n = 1225635795 and 1225635804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1225635847) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 39536625 + ... + 39536655.

It is an arithmetic number, because the mean of its divisors is an integer number (6879600).

Almost surely, 2^1225635840 is an apocalyptic number.

1225635840 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 1225635840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2641766400).

1225635840 is an abundant number, since it is smaller than the sum of its proper divisors (4057896960).

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

1225635840 is a wasteful number, since it uses less digits than its factorization.

1225635840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91 (or 65 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 1225635840 is about 35009.0822501819. The cubic root of 1225635840 is about 1070.1725753032.

The spelling of 1225635840 in words is "one billion, two hundred twenty-five million, six hundred thirty-five thousand, eight hundred forty".