21185694 has 12 divisors (see below), whose sum is σ = 45902376. Its totient is φ = 7061892.

The previous prime is 21185693. The next prime is 21185729. The reversal of 21185694 is 49658112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21185693) 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 5 ways as a sum of consecutive naturals, for example, 588474 + ... + 588509.

It is an arithmetic number, because the mean of its divisors is an integer number (3825198).

Almost surely, 2^21185694 is an apocalyptic number.

21185694 is an abundant number, since it is smaller than the sum of its proper divisors (24716682).

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

21185694 is a wasteful number, since it uses less digits than its factorization.

21185694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1176991 (or 1176988 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 21185694 is about 4602.7919787885. The cubic root of 21185694 is about 276.7032318892.

It can be divided in two parts, 211 and 85694, that added together give a triangular number (85905 = T₄₁₄).

The spelling of 21185694 in words is "twenty-one million, one hundred eighty-five thousand, six hundred ninety-four".