21689331 has 8 divisors (see below), whose sum is σ = 30620304. Its totient is φ = 13608960.

The previous prime is 21689309. The next prime is 21689341. The reversal of 21689331 is 13398612.

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

It is not a de Polignac number, because 21689331 - 2¹⁰ = 21688307 is a prime.

It is a super-2 number, since 2×21689331² = 940854158455122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 21689292 and 21689301.

It is not an unprimeable number, because it can be changed into a prime (21689341) 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, 212590 + ... + 212691.

It is an arithmetic number, because the mean of its divisors is an integer number (3827538).

Almost surely, 2^21689331 is an apocalyptic number.

21689331 is a deficient number, since it is larger than the sum of its proper divisors (8930973).

21689331 is a wasteful number, since it uses less digits than its factorization.

21689331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 425301.

The product of its digits is 7776, while the sum is 33.

The square root of 21689331 is about 4657.1805848603. The cubic root of 21689331 is about 278.8787258286.

The spelling of 21689331 in words is "twenty-one million, six hundred eighty-nine thousand, three hundred thirty-one".