21429109 has 8 divisors (see below), whose sum is σ = 23126040. Its totient is φ = 19739136.

The previous prime is 21429103. The next prime is 21429113. The reversal of 21429109 is 90192412.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 908209 + 20520900 = 953^2 + 4530^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21429109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21429103) 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, 5949 + ... + 8845.

It is an arithmetic number, because the mean of its divisors is an integer number (2890755).

Almost surely, 2^21429109 is an apocalyptic number.

It is an amenable number.

21429109 is a deficient number, since it is larger than the sum of its proper divisors (1696931).

21429109 is a wasteful number, since it uses less digits than its factorization.

21429109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3479.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 21429109 is about 4629.1585628492. The cubic root of 21429109 is about 277.7589347870.

The spelling of 21429109 in words is "twenty-one million, four hundred twenty-nine thousand, one hundred nine".