142638021 has 6 divisors (see below), whose sum is σ = 206032710. Its totient is φ = 95092008.

The previous prime is 142638011. The next prime is 142638043. The reversal of 142638021 is 120836241.

142638021 is a `hidden beast` number, since 1 + 4 + 2 + 638 + 0 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 133402500 + 9235521 = 11550^2 + 3039^2 .

It is not a de Polignac number, because 142638021 - 2¹¹ = 142635973 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (142638011) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7924326 + ... + 7924343.

It is an arithmetic number, because the mean of its divisors is an integer number (34338785).

Almost surely, 2^142638021 is an apocalyptic number.

It is an amenable number.

142638021 is a deficient number, since it is larger than the sum of its proper divisors (63394689).

142638021 is a wasteful number, since it uses less digits than its factorization.

142638021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15848675 (or 15848672 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 142638021 is about 11943.1160506796. The cubic root of 142638021 is about 522.4905438488.

The spelling of 142638021 in words is "one hundred forty-two million, six hundred thirty-eight thousand, twenty-one".