642226640 has 80 divisors (see below), whose sum is σ = 1635538176. Its totient is φ = 232588800.

The previous prime is 642226639. The next prime is 642226643. The reversal of 642226640 is 46622246.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 642226597 and 642226606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642226643) 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, 237134 + ... + 239826.

Almost surely, 2^642226640 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 642226640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (817769088).

642226640 is an abundant number, since it is smaller than the sum of its proper divisors (993311536).

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

642226640 is a wasteful number, since it uses less digits than its factorization.

642226640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2988 (or 2982 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 32.

The square root of 642226640 is about 25342.1909076544. The cubic root of 642226640 is about 862.7721255734.

Adding to 642226640 its reverse (46622246), we get a palindrome (688848886).

The spelling of 642226640 in words is "six hundred forty-two million, two hundred twenty-six thousand, six hundred forty".