642605381 has 8 divisors (see below), whose sum is σ = 719971104. Its totient is φ = 568397520.

The previous prime is 642605371. The next prime is 642605399. The reversal of 642605381 is 183506246.

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 642605381 - 2⁶ = 642605317 is a prime.

It is a super-2 number, since 2×642605381² = 825883351380310322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642605351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 789035 + ... + 789848.

It is an arithmetic number, because the mean of its divisors is an integer number (89996388).

Almost surely, 2^642605381 is an apocalyptic number.

It is an amenable number.

642605381 is a deficient number, since it is larger than the sum of its proper divisors (77365723).

642605381 is a wasteful number, since it uses less digits than its factorization.

642605381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1578931.

The product of its (nonzero) digits is 34560, while the sum is 35.

The square root of 642605381 is about 25349.6623448913. The cubic root of 642605381 is about 862.9416934193.

The spelling of 642605381 in words is "six hundred forty-two million, six hundred five thousand, three hundred eighty-one".