21158699 has 4 divisors (see below), whose sum is σ = 21170760. Its totient is φ = 21146640.

The previous prime is 21158677. The next prime is 21158701. The reversal of 21158699 is 99685112.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21158699 - 2¹² = 21154603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21158299) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2834 + ... + 7095.

It is an arithmetic number, because the mean of its divisors is an integer number (5292690).

Almost surely, 2^21158699 is an apocalyptic number.

21158699 is a deficient number, since it is larger than the sum of its proper divisors (12061).

21158699 is an equidigital number, since it uses as much as digits as its factorization.

21158699 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12060.

The product of its digits is 38880, while the sum is 41.

The square root of 21158699 is about 4599.8585847828. The cubic root of 21158699 is about 276.5856560287.

The spelling of 21158699 in words is "twenty-one million, one hundred fifty-eight thousand, six hundred ninety-nine".