642120321 has 8 divisors (see below), whose sum is σ = 856383840. Its totient is φ = 427968512.

The previous prime is 642120319. The next prime is 642120359. The reversal of 642120321 is 123021246.

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 642120321 - 2¹ = 642120319 is a prime.

It is a super-2 number, since 2×642120321² = 824637013282286082, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (642120301) 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, 13440 + ... + 38273.

It is an arithmetic number, because the mean of its divisors is an integer number (107047980).

Almost surely, 2^642120321 is an apocalyptic number.

It is an amenable number.

642120321 is a deficient number, since it is larger than the sum of its proper divisors (214263519).

642120321 is a wasteful number, since it uses less digits than its factorization.

642120321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55855.

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 642120321 is about 25340.0931529464. The cubic root of 642120321 is about 862.7245130297.

Adding to 642120321 its reverse (123021246), we get a palindrome (765141567).

The spelling of 642120321 in words is "six hundred forty-two million, one hundred twenty thousand, three hundred twenty-one".