142191221 has 4 divisors (see below), whose sum is σ = 148373472. Its totient is φ = 136008972.

The previous prime is 142191197. The next prime is 142191229. The reversal of 142191221 is 122191241.

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: 122191241 = 7607 ⋅16063.

It is a cyclic number.

It is not a de Polignac number, because 142191221 - 2²² = 137996917 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 6182227 = 142191221 / (1 + 4 + 2 + 1 + 9 + 1 + 2 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (142191229) 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, 3091091 + ... + 3091136.

It is an arithmetic number, because the mean of its divisors is an integer number (37093368).

Almost surely, 2^142191221 is an apocalyptic number.

It is an amenable number.

142191221 is a deficient number, since it is larger than the sum of its proper divisors (6182251).

142191221 is an equidigital number, since it uses as much as digits as its factorization.

142191221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6182250.

The product of its digits is 288, while the sum is 23.

The square root of 142191221 is about 11924.3960434061. The cubic root of 142191221 is about 521.9444226243.

The spelling of 142191221 in words is "one hundred forty-two million, one hundred ninety-one thousand, two hundred twenty-one".