21047827 has 2 divisors, whose sum is σ = 21047828. Its totient is φ = 21047826.

The previous prime is 21047813. The next prime is 21047833. The reversal of 21047827 is 72874012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21047827 - 2²³ = 12659219 is a prime.

It is a super-2 number, since 2×21047827² = 886022042843858, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21047527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10523913 + 10523914.

It is an arithmetic number, because the mean of its divisors is an integer number (10523914).

Almost surely, 2^21047827 is an apocalyptic number.

21047827 is a deficient number, since it is larger than the sum of its proper divisors (1).

21047827 is an equidigital number, since it uses as much as digits as its factorization.

21047827 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6272, while the sum is 31.

The square root of 21047827 is about 4587.7910806836. The cubic root of 21047827 is about 276.1017049736.

The spelling of 21047827 in words is "twenty-one million, forty-seven thousand, eight hundred twenty-seven".