142177781 has 2 divisors, whose sum is σ = 142177782. Its totient is φ = 142177780.

The previous prime is 142177769. The next prime is 142177813. The reversal of 142177781 is 187771241.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 115562500 + 26615281 = 10750^2 + 5159^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-142177781 is a prime.

It is a super-2 number, since 2×142177781² = 40429042820167922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (142176781) 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 as a sum of consecutive naturals, namely, 71088890 + 71088891.

It is an arithmetic number, because the mean of its divisors is an integer number (71088891).

Almost surely, 2^142177781 is an apocalyptic number.

142177781 is the 5333-rd centered decagonal number.

It is an amenable number.

142177781 is a deficient number, since it is larger than the sum of its proper divisors (1).

142177781 is an equidigital number, since it uses as much as digits as its factorization.

142177781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21952, while the sum is 38.

The square root of 142177781 is about 11923.8324795344. The cubic root of 142177781 is about 521.9279772722.

The spelling of 142177781 in words is "one hundred forty-two million, one hundred seventy-seven thousand, seven hundred eighty-one".