21403689 has 8 divisors (see below), whose sum is σ = 28560960. Its totient is φ = 14257776.

The previous prime is 21403687. The next prime is 21403717. The reversal of 21403689 is 98630412.

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

It is not a de Polignac number, because 21403689 - 2¹ = 21403687 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21403687) 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, 3739 + ... + 7535.

It is an arithmetic number, because the mean of its divisors is an integer number (3570120).

Almost surely, 2^21403689 is an apocalyptic number.

It is an amenable number.

21403689 is a deficient number, since it is larger than the sum of its proper divisors (7157271).

21403689 is a wasteful number, since it uses less digits than its factorization.

21403689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5679.

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 21403689 is about 4626.4121087512. The cubic root of 21403689 is about 277.6490620305.

The spelling of 21403689 in words is "twenty-one million, four hundred three thousand, six hundred eighty-nine".