643621449 has 8 divisors (see below), whose sum is σ = 858926560. Its totient is φ = 428698656.

The previous prime is 643621379. The next prime is 643621483. The reversal of 643621449 is 944126346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 643621449 - 2⁸ = 643621193 is a prime.

It is a super-2 number, since 2×643621449² = 828497139225719202, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (643621249) 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, 91627 + ... + 98400.

It is an arithmetic number, because the mean of its divisors is an integer number (107365820).

Almost surely, 2^643621449 is an apocalyptic number.

It is an amenable number.

643621449 is a deficient number, since it is larger than the sum of its proper divisors (215305111).

643621449 is a wasteful number, since it uses less digits than its factorization.

643621449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191159.

The product of its digits is 124416, while the sum is 39.

The square root of 643621449 is about 25369.6954849679. The cubic root of 643621449 is about 863.3962729300.

The spelling of 643621449 in words is "six hundred forty-three million, six hundred twenty-one thousand, four hundred forty-nine".