21266158 has 4 divisors (see below), whose sum is σ = 31899240. Its totient is φ = 10633078.

The previous prime is 21266129. The next prime is 21266171. The reversal of 21266158 is 85166212.

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

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5316538 + ... + 5316541.

It is an arithmetic number, because the mean of its divisors is an integer number (7974810).

Almost surely, 2^21266158 is an apocalyptic number.

21266158 is a deficient number, since it is larger than the sum of its proper divisors (10633082).

21266158 is a wasteful number, since it uses less digits than its factorization.

21266158 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10633081.

The product of its digits is 5760, while the sum is 31.

The square root of 21266158 is about 4611.5244767864. The cubic root of 21266158 is about 277.0530988147.

The spelling of 21266158 in words is "twenty-one million, two hundred sixty-six thousand, one hundred fifty-eight".