642405140 has 24 divisors (see below), whose sum is σ = 1452824520. Its totient is φ = 237195648.

The previous prime is 642405121. The next prime is 642405149. The reversal of 642405140 is 41504246.

It can be written as a sum of positive squares in 4 ways, for example, as 65060356 + 577344784 = 8066^2 + 24028^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642405149) 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, 1235135 + ... + 1235654.

It is an arithmetic number, because the mean of its divisors is an integer number (60534355).

Almost surely, 2^642405140 is an apocalyptic number.

It is an amenable number.

642405140 is an abundant number, since it is smaller than the sum of its proper divisors (810419380).

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

642405140 is a wasteful number, since it uses less digits than its factorization.

642405140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2470811 (or 2470809 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 26.

The square root of 642405140 is about 25345.7124579287. The cubic root of 642405140 is about 862.8520509191.

Adding to 642405140 its reverse (41504246), we get a palindrome (683909386).

The spelling of 642405140 in words is "six hundred forty-two million, four hundred five thousand, one hundred forty".