142099981 has 4 divisors (see below), whose sum is σ = 143696700. Its totient is φ = 140503264.

The previous prime is 142099961. The next prime is 142099987. The reversal of 142099981 is 189990241.

It is a happy number.

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 16883881 + 125216100 = 4109^2 + 11190^2 .

It is a cyclic number.

It is not a de Polignac number, because 142099981 - 2²¹ = 140002829 is a prime.

It is a super-2 number, since 2×142099981² = 40384809200400722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (142099987) 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 in 3 ways as a sum of consecutive naturals, for example, 798226 + ... + 798403.

It is an arithmetic number, because the mean of its divisors is an integer number (35924175).

Almost surely, 2^142099981 is an apocalyptic number.

It is an amenable number.

142099981 is a deficient number, since it is larger than the sum of its proper divisors (1596719).

142099981 is an equidigital number, since it uses as much as digits as its factorization.

142099981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1596718.

The product of its (nonzero) digits is 46656, while the sum is 43.

The square root of 142099981 is about 11920.5696592067. The cubic root of 142099981 is about 521.8327598499.

The spelling of 142099981 in words is "one hundred forty-two million, ninety-nine thousand, nine hundred eighty-one".