21058679 has 4 divisors (see below), whose sum is σ = 21506784. Its totient is φ = 20610576.

The previous prime is 21058663. The next prime is 21058711. The reversal of 21058679 is 97685012.

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

It is a cyclic number.

It is not a de Polignac number, because 21058679 - 2⁴ = 21058663 is a prime.

It is a super-2 number, since 2×21058679² = 886935922450082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21058619) 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, 223982 + ... + 224075.

It is an arithmetic number, because the mean of its divisors is an integer number (5376696).

Almost surely, 2^21058679 is an apocalyptic number.

21058679 is a deficient number, since it is larger than the sum of its proper divisors (448105).

21058679 is an equidigital number, since it uses as much as digits as its factorization.

21058679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448104.

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 21058679 is about 4588.9736325239. The cubic root of 21058679 is about 276.1491483653.

The spelling of 21058679 in words is "twenty-one million, fifty-eight thousand, six hundred seventy-nine".