21042154 has 16 divisors (see below), whose sum is σ = 36612288. Its totient is φ = 8883072.

The previous prime is 21042127. The next prime is 21042157. The reversal of 21042154 is 45124012.

It is not an unprimeable number, because it can be changed into a prime (21042157) 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 7 ways as a sum of consecutive naturals, for example, 10279 + ... + 12154.

It is an arithmetic number, because the mean of its divisors is an integer number (2288268).

Almost surely, 2^21042154 is an apocalyptic number.

21042154 is a deficient number, since it is larger than the sum of its proper divisors (15570134).

21042154 is a wasteful number, since it uses less digits than its factorization.

21042154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22509.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 21042154 is about 4587.1727676206. The cubic root of 21042154 is about 276.0768969381.

Adding to 21042154 its reverse (45124012), we get a palindrome (66166166).

The spelling of 21042154 in words is "twenty-one million, forty-two thousand, one hundred fifty-four".