21320867 has 2 divisors, whose sum is σ = 21320868. Its totient is φ = 21320866.

The previous prime is 21320863. The next prime is 21320879. The reversal of 21320867 is 76802312.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21320867 - 2² = 21320863 is a prime.

It is not a weakly prime, because it can be changed into another prime (21320863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660433 + 10660434.

It is an arithmetic number, because the mean of its divisors is an integer number (10660434).

Almost surely, 2^21320867 is an apocalyptic number.

21320867 is a deficient number, since it is larger than the sum of its proper divisors (1).

21320867 is an equidigital number, since it uses as much as digits as its factorization.

21320867 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 21320867 is about 4617.4524361384. The cubic root of 21320867 is about 277.2904762591.

It can be divided in two parts, 213 and 20867, that multiplied together give a triangular number (4444671 = T₂₉₈₁).

The spelling of 21320867 in words is "twenty-one million, three hundred twenty thousand, eight hundred sixty-seven".