21178134 has 24 divisors (see below), whose sum is σ = 47127600. Its totient is φ = 6868368.

The previous prime is 21178133. The next prime is 21178151. The reversal of 21178134 is 43187112.

It is a junction number, because it is equal to n+sod(n) for n = 21178098 and 21178107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21178133) 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 11 ways as a sum of consecutive naturals, for example, 15234 + ... + 16565.

It is an arithmetic number, because the mean of its divisors is an integer number (1963650).

Almost surely, 2^21178134 is an apocalyptic number.

21178134 is an abundant number, since it is smaller than the sum of its proper divisors (25949466).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21178134 is a wasteful number, since it uses less digits than its factorization.

21178134 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31844 (or 31841 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 21178134 is about 4601.9706648348. The cubic root of 21178134 is about 276.6703146242.

It can be divided in two parts, 21178 and 134, that added together give a palindrome (21312).

The spelling of 21178134 in words is "twenty-one million, one hundred seventy-eight thousand, one hundred thirty-four".