142171921 has 4 divisors (see below), whose sum is σ = 146758144. Its totient is φ = 137585700.

The previous prime is 142171903. The next prime is 142171957. The reversal of 142171921 is 129171241.

142171921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 129171241 = 79 ⋅1635079.

It is a cyclic number.

It is not a de Polignac number, because 142171921 - 2⁷ = 142171793 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 142171921.

It is not an unprimeable number, because it can be changed into a prime (142171961) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2293065 + ... + 2293126.

It is an arithmetic number, because the mean of its divisors is an integer number (36689536).

Almost surely, 2^142171921 is an apocalyptic number.

It is an amenable number.

142171921 is a deficient number, since it is larger than the sum of its proper divisors (4586223).

142171921 is an equidigital number, since it uses as much as digits as its factorization.

142171921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4586222.

The product of its digits is 1008, while the sum is 28.

The square root of 142171921 is about 11923.5867506384. The cubic root of 142171921 is about 521.9208065785.

The spelling of 142171921 in words is "one hundred forty-two million, one hundred seventy-one thousand, nine hundred twenty-one".