21489843 has 8 divisors (see below), whose sum is σ = 29899008. Its totient is φ = 13703624.

The previous prime is 21489833. The next prime is 21489877. The reversal of 21489843 is 34898412.

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

It is a cyclic number.

It is not a de Polignac number, because 21489843 - 2⁴ = 21489827 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21489803) 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, 155655 + ... + 155792.

It is an arithmetic number, because the mean of its divisors is an integer number (3737376).

Almost surely, 2^21489843 is an apocalyptic number.

21489843 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21489843 is a deficient number, since it is larger than the sum of its proper divisors (8409165).

21489843 is a wasteful number, since it uses less digits than its factorization.

21489843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311473.

The product of its digits is 55296, while the sum is 39.

The square root of 21489843 is about 4635.7138608849. The cubic root of 21489843 is about 278.0210937534.

The spelling of 21489843 in words is "twenty-one million, four hundred eighty-nine thousand, eight hundred forty-three".