642145856 has 56 divisors (see below), whose sum is σ = 1393021344. Its totient is φ = 291271680.

The previous prime is 642145849. The next prime is 642145859. The reversal of 642145856 is 658541246.

It is not an unprimeable number, because it can be changed into a prime (642145859) 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, 621116 + ... + 622148.

Almost surely, 2^642145856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642145856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (696510672).

642145856 is an abundant number, since it is smaller than the sum of its proper divisors (750875488).

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

642145856 is a wasteful number, since it uses less digits than its factorization.

642145856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1939 (or 1929 counting only the distinct ones).

The product of its digits is 230400, while the sum is 41.

The square root of 642145856 is about 25340.5969937569. The cubic root of 642145856 is about 862.7359487776.

The spelling of 642145856 in words is "six hundred forty-two million, one hundred forty-five thousand, eight hundred fifty-six".