642857670 has 192 divisors, whose sum is σ = 2097373824. Its totient is φ = 132986880.

The previous prime is 642857653. The next prime is 642857701. The reversal of 642857670 is 76758246.

642857670 is a `hidden beast` number, since 6 + 4 + 2 + 8 + 576 + 70 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 433330 + ... + 434810.

It is an arithmetic number, because the mean of its divisors is an integer number (10923822).

Almost surely, 2^642857670 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642857670, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1048686912).

642857670 is an abundant number, since it is smaller than the sum of its proper divisors (1454516154).

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

642857670 is a wasteful number, since it uses less digits than its factorization.

642857670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1567 (or 1564 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 45.

The square root of 642857670 is about 25354.6380372507. The cubic root of 642857670 is about 863.0546098986.

The spelling of 642857670 in words is "six hundred forty-two million, eight hundred fifty-seven thousand, six hundred seventy".