21729694 has 8 divisors (see below), whose sum is σ = 37250928. Its totient is φ = 9312720.

The previous prime is 21729683. The next prime is 21729709. The reversal of 21729694 is 49692712.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 776047 + ... + 776074.

It is an arithmetic number, because the mean of its divisors is an integer number (4656366).

Almost surely, 2^21729694 is an apocalyptic number.

21729694 is a deficient number, since it is larger than the sum of its proper divisors (15521234).

21729694 is a wasteful number, since it uses less digits than its factorization.

21729694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1552130.

The product of its digits is 54432, while the sum is 40.

The square root of 21729694 is about 4661.5119864696. The cubic root of 21729694 is about 279.0516127756.

The spelling of 21729694 in words is "twenty-one million, seven hundred twenty-nine thousand, six hundred ninety-four".