643952541488400 has 315 divisors, whose sum is σ = 2319632224263039. Its totient is φ = 171717023554560.

The previous prime is 643952541488393. The next prime is 643952541488449. The reversal of 643952541488400 is 4884145259346.

The square root of 643952541488400 is 25376220.

It is a perfect power (a square), and thus also a powerful number.

643952541488400 is a `hidden beast` number, since 6 + 4 + 3 + 9 + 5 + 2 + 541 + 4 + 8 + 84 + 0 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 282993276339216 + 360959265149184 = 16822404^2 + 18998928^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 62 ways as a sum of consecutive naturals, for example, 13703135304 + ... + 13703182296.

Almost surely, 2^{643952541488400} is an apocalyptic number.

643952541488400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

643952541488400 is the 25376220-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643952541488400

643952541488400 is an abundant number, since it is smaller than the sum of its proper divisors (1675679682774639).

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

643952541488400 is an frugal number, since it uses more digits than its factorization.

643952541488400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94022 (or 47003 counting only the distinct ones).

The product of its (nonzero) digits is 132710400, while the sum is 63.

The spelling of 643952541488400 in words is "six hundred forty-three trillion, nine hundred fifty-two billion, five hundred forty-one million, four hundred eighty-eight thousand, four hundred".