21729094 has 8 divisors (see below), whose sum is σ = 34510968. Its totient is φ = 10225440.

The previous prime is 21729079. The next prime is 21729119. The reversal of 21729094 is 49092712.

It is a happy number.

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

It is a Harshad number since it is a multiple of its sum of digits (34), and also a Moran number because the ratio is a prime number: 639091 = 21729094 / (2 + 1 + 7 + 2 + 9 + 0 + 9 + 4).

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, 319512 + ... + 319579.

It is an arithmetic number, because the mean of its divisors is an integer number (4313871).

Almost surely, 2^21729094 is an apocalyptic number.

21729094 is a deficient number, since it is larger than the sum of its proper divisors (12781874).

21729094 is a wasteful number, since it uses less digits than its factorization.

21729094 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 639110.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 21729094 is about 4661.4476292242. The cubic root of 21729094 is about 279.0490443622.

The spelling of 21729094 in words is "twenty-one million, seven hundred twenty-nine thousand, ninety-four".