643021101 has 12 divisors (see below), whose sum is σ = 937490112. Its totient is φ = 424673736.

The previous prime is 643021063. The next prime is 643021111. The reversal of 643021101 is 101120346.

It is a happy number.

643021101 is a `hidden beast` number, since 643 + 0 + 21 + 1 + 0 + 1 = 666.

It is not a de Polignac number, because 643021101 - 2¹⁴ = 643004717 is a prime.

It is a super-2 number, since 2×643021101² = 826952272662504402, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643021111) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 332901 + ... + 334826.

It is an arithmetic number, because the mean of its divisors is an integer number (78124176).

Almost surely, 2^643021101 is an apocalyptic number.

It is an amenable number.

643021101 is a deficient number, since it is larger than the sum of its proper divisors (294469011).

643021101 is a wasteful number, since it uses less digits than its factorization.

643021101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 667840 (or 667837 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 643021101 is about 25357.8607339026. The cubic root of 643021101 is about 863.1277406155.

Adding to 643021101 its reverse (101120346), we get a palindrome (744141447).

The spelling of 643021101 in words is "six hundred forty-three million, twenty-one thousand, one hundred one".