642157740 has 192 divisors, whose sum is σ = 2330496000. Its totient is φ = 146736576.

The previous prime is 642157739. The next prime is 642157781. The reversal of 642157740 is 47751246.

642157740 is a `hidden beast` number, since 6 + 42 + 1 + 577 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 642157695 and 642157704.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 183487 + ... + 186953.

It is an arithmetic number, because the mean of its divisors is an integer number (12138000).

Almost surely, 2^642157740 is an apocalyptic number.

642157740 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642157740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1165248000).

642157740 is an abundant number, since it is smaller than the sum of its proper divisors (1688338260).

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

642157740 is a wasteful number, since it uses less digits than its factorization.

642157740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3506 (or 3484 counting only the distinct ones).

The product of its (nonzero) digits is 47040, while the sum is 36.

The square root of 642157740 is about 25340.8314780711. The cubic root of 642157740 is about 862.7412708762.

The spelling of 642157740 in words is "six hundred forty-two million, one hundred fifty-seven thousand, seven hundred forty".