21430929 has 8 divisors (see below), whose sum is σ = 30772672. Its totient is φ = 13188240.

The previous prime is 21430909. The next prime is 21430949. The reversal of 21430929 is 92903412.

It is an interprime number because it is at equal distance from previous prime (21430909) and next prime (21430949).

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

It is not a de Polignac number, because 21430929 - 2¹⁷ = 21299857 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21430896 and 21430905.

It is not an unprimeable number, because it can be changed into a prime (21430909) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 274717 + ... + 274794.

It is an arithmetic number, because the mean of its divisors is an integer number (3846584).

Almost surely, 2^21430929 is an apocalyptic number.

It is an amenable number.

21430929 is a deficient number, since it is larger than the sum of its proper divisors (9341743).

21430929 is a wasteful number, since it uses less digits than its factorization.

21430929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 549527.

The product of its (nonzero) digits is 3888, while the sum is 30.

The square root of 21430929 is about 4629.3551386775. The cubic root of 21430929 is about 277.7667980312.

The spelling of 21430929 in words is "twenty-one million, four hundred thirty thousand, nine hundred twenty-nine".