642005213 has 4 divisors (see below), whose sum is σ = 643530588. Its totient is φ = 640479840.

The previous prime is 642005209. The next prime is 642005239. The reversal of 642005213 is 312500246.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 312500246 = 2 ⋅156250123.

It can be written as a sum of positive squares in 2 ways, for example, as 56220004 + 585785209 = 7498^2 + 24203^2 .

It is a cyclic number.

It is not a de Polignac number, because 642005213 - 2² = 642005209 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642005293) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 762056 + ... + 762897.

It is an arithmetic number, because the mean of its divisors is an integer number (160882647).

Almost surely, 2^642005213 is an apocalyptic number.

It is an amenable number.

642005213 is a deficient number, since it is larger than the sum of its proper divisors (1525375).

642005213 is a wasteful number, since it uses less digits than its factorization.

642005213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1525374.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 642005213 is about 25337.8217887805. The cubic root of 642005213 is about 862.6729586067.

Adding to 642005213 its reverse (312500246), we get a palindrome (954505459).

The spelling of 642005213 in words is "six hundred forty-two million, five thousand, two hundred thirteen".