21872663 has 2 divisors, whose sum is σ = 21872664. Its totient is φ = 21872662.

The previous prime is 21872647. The next prime is 21872689. The reversal of 21872663 is 36627812.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21872663 - 2⁴ = 21872647 is a prime.

It is a Sophie Germain prime.

It is equal to p_1381688 and since 21872663 and 1381688 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21872603) 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, 10936331 + 10936332.

It is an arithmetic number, because the mean of its divisors is an integer number (10936332).

Almost surely, 2^21872663 is an apocalyptic number.

21872663 is a deficient number, since it is larger than the sum of its proper divisors (1).

21872663 is an equidigital number, since it uses as much as digits as its factorization.

21872663 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24192, while the sum is 35.

The square root of 21872663 is about 4676.8218909854. The cubic root of 21872663 is about 279.6622756378.

The spelling of 21872663 in words is "twenty-one million, eight hundred seventy-two thousand, six hundred sixty-three".