643751080281 has 45 divisors (see below), whose sum is σ = 978876139813. Its totient is φ = 421614148680.

The previous prime is 643751080211. The next prime is 643751080289. The reversal of 643751080281 is 182080157346.

The square root of 643751080281 is 802341.

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

643751080281 is a `hidden beast` number, since 6 + 4 + 37 + 510 + 80 + 28 + 1 = 666.

It is not a de Polignac number, because 643751080281 - 2⁷ = 643751080153 is a prime.

It is a super-2 number, since 2×643751080281² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643751080289) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 426042316 + ... + 426043826.

Almost surely, 2^643751080281 is an apocalyptic number.

643751080281 is the 802341-st square number.

643751080281 is the 401171-st centered octagonal number.

It is an amenable number.

643751080281 is a deficient number, since it is larger than the sum of its proper divisors (335125059532).

643751080281 is an frugal number, since it uses more digits than its factorization.

643751080281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3152 (or 1573 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The spelling of 643751080281 in words is "six hundred forty-three billion, seven hundred fifty-one million, eighty thousand, two hundred eighty-one".