21158227 has 4 divisors (see below), whose sum is σ = 21205800. Its totient is φ = 21110656.

The previous prime is 21158201. The next prime is 21158231. The reversal of 21158227 is 72285112.

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 21158227 - 2²³ = 12769619 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21158195 and 21158204.

It is not an unprimeable number, because it can be changed into a prime (21158257) 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, 23113 + ... + 24010.

It is an arithmetic number, because the mean of its divisors is an integer number (5301450).

Almost surely, 2^21158227 is an apocalyptic number.

21158227 is a deficient number, since it is larger than the sum of its proper divisors (47573).

21158227 is an equidigital number, since it uses as much as digits as its factorization.

21158227 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47572.

The product of its digits is 2240, while the sum is 28.

The square root of 21158227 is about 4599.8072785716. The cubic root of 21158227 is about 276.5835993585.

The spelling of 21158227 in words is "twenty-one million, one hundred fifty-eight thousand, two hundred twenty-seven".