21239458 has 4 divisors (see below), whose sum is σ = 31859190. Its totient is φ = 10619728.

The previous prime is 21239453. The next prime is 21239459. The reversal of 21239458 is 85493212.

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

It can be written as a sum of positive squares in only one way, i.e., 12341169 + 8898289 = 3513^2 + 2983^2 .

It is a super-2 number, since 2×21239458² = 902229152267528, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21239453) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5309863 + ... + 5309866.

Almost surely, 2^21239458 is an apocalyptic number.

21239458 is a deficient number, since it is larger than the sum of its proper divisors (10619732).

21239458 is a wasteful number, since it uses less digits than its factorization.

21239458 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10619731.

The product of its digits is 17280, while the sum is 34.

The square root of 21239458 is about 4608.6286463546. The cubic root of 21239458 is about 276.9371020635.

The spelling of 21239458 in words is "twenty-one million, two hundred thirty-nine thousand, four hundred fifty-eight".