642081 has 8 divisors (see below), whose sum is σ = 933984. Its totient is φ = 389120.

The previous prime is 642079. The next prime is 642113. The reversal of 642081 is 180246.

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 642081 - 2¹ = 642079 is a prime.

It is a super-2 number, since 2×642081² = 824536021122, which contains 22 as substring.

642081 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (642011) 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, 9696 + ... + 9761.

It is an arithmetic number, because the mean of its divisors is an integer number (116748).

2⁶⁴²⁰⁸¹ is an apocalyptic number.

It is an amenable number.

642081 is a deficient number, since it is larger than the sum of its proper divisors (291903).

642081 is a wasteful number, since it uses less digits than its factorization.

642081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19471.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 642081 is about 801.2995694495. The cubic root of 642081 is about 86.2706902684.

It can be divided in two parts, 64 and 2081, that added together give a triangular number (2145 = T₆₅).

The spelling of 642081 in words is "six hundred forty-two thousand, eighty-one".