642669 has 16 divisors (see below), whose sum is σ = 907200. Its totient is φ = 404096.

The previous prime is 642623. The next prime is 642673. The reversal of 642669 is 966246.

642669 = 37² + 38² + ... + 125².

It is a cyclic number.

It is not a de Polignac number, because 642669 - 2⁹ = 642157 is a prime.

It is a super-2 number, since 2×642669² = 826046887122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642769) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7177 + ... + 7265.

It is an arithmetic number, because the mean of its divisors is an integer number (56700).

2⁶⁴²⁶⁶⁹ is an apocalyptic number.

It is an amenable number.

642669 is a deficient number, since it is larger than the sum of its proper divisors (264531).

642669 is a wasteful number, since it uses less digits than its factorization.

642669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204.

The product of its digits is 15552, while the sum is 33.

The square root of 642669 is about 801.6663894663. Note that the first 3 decimals coincide. The cubic root of 642669 is about 86.2970170033.

The spelling of 642669 in words is "six hundred forty-two thousand, six hundred sixty-nine".