21429818 has 8 divisors (see below), whose sum is σ = 32313600. Its totient is φ = 10658620.

The previous prime is 21429817. The next prime is 21429827. The reversal of 21429818 is 81892412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21429817) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27668 + ... + 28431.

It is an arithmetic number, because the mean of its divisors is an integer number (4039200).

Almost surely, 2^21429818 is an apocalyptic number.

21429818 is a deficient number, since it is larger than the sum of its proper divisors (10883782).

21429818 is a wasteful number, since it uses less digits than its factorization.

21429818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56292.

The product of its digits is 9216, while the sum is 35.

The square root of 21429818 is about 4629.2351420078. The cubic root of 21429818 is about 277.7619980488.

It can be divided in two parts, 2 and 1429818, that multiplied together give a triangular number (2859636 = T₂₃₉₁).

The spelling of 21429818 in words is "twenty-one million, four hundred twenty-nine thousand, eight hundred eighteen".