1643778472 has 32 divisors (see below), whose sum is σ = 3636011520. Its totient is φ = 681750720.

The previous prime is 1643778463. The next prime is 1643778473. The reversal of 1643778472 is 2748773461.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (1643778473) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 471703 + ... + 475174.

It is an arithmetic number, because the mean of its divisors is an integer number (113625360).

Almost surely, 2^1643778472 is an apocalyptic number.

It is an amenable number.

1643778472 is an abundant number, since it is smaller than the sum of its proper divisors (1992233048).

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

1643778472 is a wasteful number, since it uses less digits than its factorization.

1643778472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 946921 (or 946917 counting only the distinct ones).

The product of its digits is 1580544, while the sum is 49.

The square root of 1643778472 is about 40543.5379807929. The cubic root of 1643778472 is about 1180.1786744665.

The spelling of 1643778472 in words is "one billion, six hundred forty-three million, seven hundred seventy-eight thousand, four hundred seventy-two".