21142120042 has 4 divisors (see below), whose sum is σ = 31713180066. Its totient is φ = 10571060020.

The previous prime is 21142119937. The next prime is 21142120061. The reversal of 21142120042 is 24002124112.

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

It can be written as a sum of positive squares in only one way, i.e., 19149301161 + 1992818881 = 138381^2 + 44641^2 .

It is an unprimeable number.

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, 5285530009 + ... + 5285530012.

Almost surely, 2^21142120042 is an apocalyptic number.

21142120042 is a deficient number, since it is larger than the sum of its proper divisors (10571060024).

21142120042 is a wasteful number, since it uses less digits than its factorization.

21142120042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10571060023.

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 21142120042 its reverse (24002124112), we get a palindrome (45144244154).

The spelling of 21142120042 in words is "twenty-one billion, one hundred forty-two million, one hundred twenty thousand, forty-two".