21381658 has 8 divisors (see below), whose sum is σ = 32367060. Its totient is φ = 10592640.

The previous prime is 21381653. The next prime is 21381739. The reversal of 21381658 is 85618312.

It can be written as a sum of positive squares in 2 ways, for example, as 20548089 + 833569 = 4533^2 + 913^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21381653) 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, 48823 + ... + 49258.

Almost surely, 2^21381658 is an apocalyptic number.

21381658 is a deficient number, since it is larger than the sum of its proper divisors (10985402).

21381658 is a wasteful number, since it uses less digits than its factorization.

21381658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98192.

The product of its digits is 11520, while the sum is 34.

The square root of 21381658 is about 4624.0304929790. The cubic root of 21381658 is about 277.5537671430.

The spelling of 21381658 in words is "twenty-one million, three hundred eighty-one thousand, six hundred fifty-eight".