21142151 has 4 divisors (see below), whose sum is σ = 21592032. Its totient is φ = 20692272.

The previous prime is 21142141. The next prime is 21142153. The reversal of 21142151 is 15124112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21142151 - 2⁶ = 21142087 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21142153) 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, 224870 + ... + 224963.

It is an arithmetic number, because the mean of its divisors is an integer number (5398008).

Almost surely, 2^21142151 is an apocalyptic number.

21142151 is a deficient number, since it is larger than the sum of its proper divisors (449881).

21142151 is an equidigital number, since it uses as much as digits as its factorization.

21142151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 449880.

The product of its digits is 80, while the sum is 17.

The square root of 21142151 is about 4598.0594819989. The cubic root of 21142151 is about 276.5135322945.

Adding to 21142151 its reverse (15124112), we get a palindrome (36266263).

The spelling of 21142151 in words is "twenty-one million, one hundred forty-two thousand, one hundred fifty-one".