21058919 has 4 divisors (see below), whose sum is σ = 24067344. Its totient is φ = 18050496.

The previous prime is 21058907. The next prime is 21058931. The reversal of 21058919 is 91985012.

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

It is an interprime number because it is at equal distance from previous prime (21058907) and next prime (21058931).

It is a cyclic number.

It is not a de Polignac number, because 21058919 - 2⁸ = 21058663 is a prime.

It is a super-2 number, since 2×21058919² = 886956138897122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21058979) 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, 1504202 + ... + 1504215.

It is an arithmetic number, because the mean of its divisors is an integer number (6016836).

Almost surely, 2^21058919 is an apocalyptic number.

21058919 is a deficient number, since it is larger than the sum of its proper divisors (3008425).

21058919 is an equidigital number, since it uses as much as digits as its factorization.

21058919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3008424.

The product of its (nonzero) digits is 6480, while the sum is 35.

The square root of 21058919 is about 4588.9997820876. Note that the first 3 decimals coincide. The cubic root of 21058919 is about 276.1501974267.

The spelling of 21058919 in words is "twenty-one million, fifty-eight thousand, nine hundred nineteen".