1643321925 has 60 divisors (see below), whose sum is σ = 3478887456. Its totient is φ = 751226400.

The previous prime is 1643321923. The next prime is 1643321929. The reversal of 1643321925 is 5291233461.

1643321925 is a `hidden beast` number, since 1 + 6 + 433 + 219 + 2 + 5 = 666.

It is not a de Polignac number, because 1643321925 - 2¹ = 1643321923 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1643321925.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643321923) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 43791 + ... + 72140.

Almost surely, 2^1643321925 is an apocalyptic number.

1643321925 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1643321925 is an abundant number, since it is smaller than the sum of its proper divisors (1835565531).

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

1643321925 is a wasteful number, since it uses less digits than its factorization.

1643321925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115960 (or 115946 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 1643321925 is about 40537.9072597489. The cubic root of 1643321925 is about 1180.0694024582.

The spelling of 1643321925 in words is "one billion, six hundred forty-three million, three hundred twenty-one thousand, nine hundred twenty-five".