642920 has 16 divisors (see below), whose sum is σ = 1446660. Its totient is φ = 257152.

The previous prime is 642907. The next prime is 642931. The reversal of 642920 is 29246.

It can be written as a sum of positive squares in 2 ways, for example, as 605284 + 37636 = 778^2 + 194^2 .

It is a super-2 number, since 2×642920² = 826692252800, which contains 22 as substring.

It is a nialpdrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642920.

It is an unprimeable number.

642920 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7997 + ... + 8076.

2⁶⁴²⁹²⁰ is an apocalyptic number.

It is an amenable number.

642920 is an abundant number, since it is smaller than the sum of its proper divisors (803740).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

642920 is a wasteful number, since it uses less digits than its factorization.

642920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16084 (or 16080 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 642920 is about 801.8229230946. The cubic root of 642920 is about 86.3082502260.

The spelling of 642920 in words is "six hundred forty-two thousand, nine hundred twenty".