21019827 has 6 divisors (see below), whose sum is σ = 28037028. Its totient is φ = 14007924.

The previous prime is 21019799. The next prime is 21019841. The reversal of 21019827 is 72891012.

It is not a de Polignac number, because 21019827 - 2⁷ = 21019699 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21019794 and 21019803.

It is not an unprimeable number, because it can be changed into a prime (21019127) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6618 + ... + 9264.

It is an arithmetic number, because the mean of its divisors is an integer number (4672838).

Almost surely, 2^21019827 is an apocalyptic number.

21019827 is a deficient number, since it is larger than the sum of its proper divisors (7017201).

21019827 is an frugal number, since it uses more digits than its factorization.

21019827 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5297 (or 2650 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 21019827 is about 4584.7384876348. The cubic root of 21019827 is about 275.9792176118.

The spelling of 21019827 in words is "twenty-one million, nineteen thousand, eight hundred twenty-seven".