21142043 has 4 divisors (see below), whose sum is σ = 22768368. Its totient is φ = 19515720.

The previous prime is 21142021. The next prime is 21142061. The reversal of 21142043 is 34024112.

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 21142043 - 2⁸ = 21141787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21142243) 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, 813143 + ... + 813168.

It is an arithmetic number, because the mean of its divisors is an integer number (5692092).

Almost surely, 2^21142043 is an apocalyptic number.

21142043 is a deficient number, since it is larger than the sum of its proper divisors (1626325).

21142043 is a wasteful number, since it uses less digits than its factorization.

21142043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1626324.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 21142043 is about 4598.0477378992. The cubic root of 21142043 is about 276.5130614577.

Adding to 21142043 its reverse (34024112), we get a palindrome (55166155).

It can be divided in two parts, 21 and 142043, that multiplied together give a triangular number (2982903 = T₂₄₄₂).

The spelling of 21142043 in words is "twenty-one million, one hundred forty-two thousand, forty-three".