142815821 has 2 divisors, whose sum is σ = 142815822. Its totient is φ = 142815820.

The previous prime is 142815817. The next prime is 142815851. The reversal of 142815821 is 128518241.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 99400900 + 43414921 = 9970^2 + 6589^2 .

It is a cyclic number.

It is not a de Polignac number, because 142815821 - 2² = 142815817 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (142815851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 71407910 + 71407911.

It is an arithmetic number, because the mean of its divisors is an integer number (71407911).

Almost surely, 2^142815821 is an apocalyptic number.

It is an amenable number.

142815821 is a deficient number, since it is larger than the sum of its proper divisors (1).

142815821 is an equidigital number, since it uses as much as digits as its factorization.

142815821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5120, while the sum is 32.

The square root of 142815821 is about 11950.5573510192. The cubic root of 142815821 is about 522.7075506116.

It can be divided in two parts, 14281 and 5821, that added together give a palindrome (20102).

The spelling of 142815821 in words is "one hundred forty-two million, eight hundred fifteen thousand, eight hundred twenty-one".