642817026 has 64 divisors (see below), whose sum is σ = 1473638400. Its totient is φ = 207592848.

The previous prime is 642817013. The next prime is 642817027. The reversal of 642817026 is 620718246.

642817026 is a `hidden beast` number, since 642 + 8 + 1 + 7 + 0 + 2 + 6 = 666.

It is not an unprimeable number, because it can be changed into a prime (642817027) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 260185 + ... + 262643.

It is an arithmetic number, because the mean of its divisors is an integer number (23025600).

Almost surely, 2^642817026 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642817026, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (736819200).

642817026 is an abundant number, since it is smaller than the sum of its proper divisors (830821374).

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

642817026 is a wasteful number, since it uses less digits than its factorization.

642817026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2620 (or 2614 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The square root of 642817026 is about 25353.8365144212. The cubic root of 642817026 is about 863.0364209420.

The spelling of 642817026 in words is "six hundred forty-two million, eight hundred seventeen thousand, twenty-six".