21586867 has 2 divisors, whose sum is σ = 21586868. Its totient is φ = 21586866.

The previous prime is 21586853. The next prime is 21586879. The reversal of 21586867 is 76868512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21586867 - 2⁷ = 21586739 is a prime.

It is not a weakly prime, because it can be changed into another prime (21586837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10793433 + 10793434.

It is an arithmetic number, because the mean of its divisors is an integer number (10793434).

Almost surely, 2^21586867 is an apocalyptic number.

21586867 is a deficient number, since it is larger than the sum of its proper divisors (1).

21586867 is an equidigital number, since it uses as much as digits as its factorization.

21586867 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 161280, while the sum is 43.

The square root of 21586867 is about 4646.1669147804. The cubic root of 21586867 is about 278.4388759939.

It can be divided in two parts, 2158 and 6867, that added together give a square (9025 = 95²).

The spelling of 21586867 in words is "twenty-one million, five hundred eighty-six thousand, eight hundred sixty-seven".