21589431 has 4 divisors (see below), whose sum is σ = 28785912. Its totient is φ = 14392952.

The previous prime is 21589409. The next prime is 21589459. The reversal of 21589431 is 13498512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21589431 - 2⁶ = 21589367 is a prime.

It is a super-2 number, since 2×21589431² = 932207061807522, which contains 22 as substring.

It is a plaindrome in base 8.

It is a junction number, because it is equal to n+sod(n) for n = 21589392 and 21589401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21589471) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3598236 + ... + 3598241.

It is an arithmetic number, because the mean of its divisors is an integer number (7196478).

Almost surely, 2^21589431 is an apocalyptic number.

21589431 is a deficient number, since it is larger than the sum of its proper divisors (7196481).

21589431 is an equidigital number, since it uses as much as digits as its factorization.

21589431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7196480.

The product of its digits is 8640, while the sum is 33.

The square root of 21589431 is about 4646.4428329637. The cubic root of 21589431 is about 278.4498995021.

The spelling of 21589431 in words is "twenty-one million, five hundred eighty-nine thousand, four hundred thirty-one".