643577 has 8 divisors (see below), whose sum is σ = 719712. Its totient is φ = 570400.

The previous prime is 643567. The next prime is 643583. The reversal of 643577 is 775346.

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

It is a cyclic number.

It is not a de Polignac number, because 643577 - 2¹⁶ = 578041 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (643507) 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, 263 + ... + 1164.

It is an arithmetic number, because the mean of its divisors is an integer number (89964).

2⁶⁴³⁵⁷⁷ is an apocalyptic number.

It is an amenable number.

643577 is a deficient number, since it is larger than the sum of its proper divisors (76135).

643577 is a wasteful number, since it uses less digits than its factorization.

643577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1479.

The product of its digits is 17640, while the sum is 32.

The square root of 643577 is about 802.2325099371. The cubic root of 643577 is about 86.3376396865.

Subtracting from 643577 its sum of digits (32), we obtain a triangular number (643545 = T₁₁₃₄).

Subtracting 643577 from its reverse (775346), we obtain a square (131769 = 363²).

The spelling of 643577 in words is "six hundred forty-three thousand, five hundred seventy-seven".