643566426 has 32 divisors (see below), whose sum is σ = 1295638848. Its totient is φ = 213110400.

The previous prime is 643566421. The next prime is 643566431. The reversal of 643566426 is 624665346.

It is an interprime number because it is at equal distance from previous prime (643566421) and next prime (643566431).

It is not an unprimeable number, because it can be changed into a prime (643566421) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1070526 + ... + 1071126.

It is an arithmetic number, because the mean of its divisors is an integer number (40488714).

Almost surely, 2^643566426 is an apocalyptic number.

643566426 is an abundant number, since it is smaller than the sum of its proper divisors (652072422).

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

643566426 is a wasteful number, since it uses less digits than its factorization.

643566426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1486.

The product of its digits is 622080, while the sum is 42.

The square root of 643566426 is about 25368.6110380525. The cubic root of 643566426 is about 863.3716684014.

The spelling of 643566426 in words is "six hundred forty-three million, five hundred sixty-six thousand, four hundred twenty-six".