142040021 has 4 divisors (see below), whose sum is σ = 142368492. Its totient is φ = 141711552.

The previous prime is 142040009. The next prime is 142040023. The reversal of 142040021 is 120040241.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19140625 + 122899396 = 4375^2 + 11086^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-142040021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 142039978 and 142040005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (142040023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 163586 + ... + 164451.

It is an arithmetic number, because the mean of its divisors is an integer number (35592123).

Almost surely, 2^142040021 is an apocalyptic number.

It is an amenable number.

142040021 is a deficient number, since it is larger than the sum of its proper divisors (328471).

142040021 is an equidigital number, since it uses as much as digits as its factorization.

142040021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328470.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 142040021 is about 11918.0544133680. The cubic root of 142040021 is about 521.7593526287.

Adding to 142040021 its reverse (120040241), we get a palindrome (262080262).

The spelling of 142040021 in words is "one hundred forty-two million, forty thousand, twenty-one".