643276781400 has 96 divisors (see below), whose sum is σ = 2175445137600. Its totient is φ = 155945884800.

The previous prime is 643276781393. The next prime is 643276781429. The reversal of 643276781400 is 4187672346.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 643276781400.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 48726490 + ... + 48739689.

It is an arithmetic number, because the mean of its divisors is an integer number (22660886850).

Almost surely, 2^643276781400 is an apocalyptic number.

643276781400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643276781400 is an abundant number, since it is smaller than the sum of its proper divisors (1532168356200).

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

643276781400 is a wasteful number, since it uses less digits than its factorization.

643276781400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97466209 (or 97466200 counting only the distinct ones).

The product of its (nonzero) digits is 1354752, while the sum is 48.

The spelling of 643276781400 in words is "six hundred forty-three billion, two hundred seventy-six million, seven hundred eighty-one thousand, four hundred".