643128279764 has 24 divisors (see below), whose sum is σ = 1157179502976. Its totient is φ = 312563448000.

The previous prime is 643128279727. The next prime is 643128279769. The reversal of 643128279764 is 467972821346.

It is a happy number.

It is a super-2 number, since 2×643128279764² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643128279769) 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, 7190822 + ... + 7279709.

It is an arithmetic number, because the mean of its divisors is an integer number (48215812624).

Almost surely, 2^643128279764 is an apocalyptic number.

It is an amenable number.

643128279764 is a deficient number, since it is larger than the sum of its proper divisors (514051223212).

643128279764 is a wasteful number, since it uses less digits than its factorization.

643128279764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14470847 (or 14470845 counting only the distinct ones).

The product of its digits is 24385536, while the sum is 59.

The spelling of 643128279764 in words is "six hundred forty-three billion, one hundred twenty-eight million, two hundred seventy-nine thousand, seven hundred sixty-four".