638242143 has 16 divisors (see below), whose sum is σ = 1060974336. Its totient is φ = 331554240.

The previous prime is 638242141. The next prime is 638242147. The reversal of 638242143 is 341242836.

It is not a de Polignac number, because 638242143 - 2¹ = 638242141 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638242141) 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, 1381246 + ... + 1381707.

It is an arithmetic number, because the mean of its divisors is an integer number (66310896).

Almost surely, 2^638242143 is an apocalyptic number.

638242143 is a deficient number, since it is larger than the sum of its proper divisors (422732193).

638242143 is a wasteful number, since it uses less digits than its factorization.

638242143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2762974.

The product of its digits is 27648, while the sum is 33.

The square root of 638242143 is about 25263.4546925000. The cubic root of 638242143 is about 860.9841550203.

Adding to 638242143 its reverse (341242836), we get a palindrome (979484979).

The spelling of 638242143 in words is "six hundred thirty-eight million, two hundred forty-two thousand, one hundred forty-three".