21767869 has 2 divisors, whose sum is σ = 21767870. Its totient is φ = 21767868.

The previous prime is 21767839. The next prime is 21767899. The reversal of 21767869 is 96876712.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (21767839) and next prime (21767899).

It can be written as a sum of positive squares in only one way, i.e., 21576025 + 191844 = 4645^2 + 438^2 .

It is a cyclic number.

It is not a de Polignac number, because 21767869 - 2⁹ = 21767357 is a prime.

It is a super-2 number, since 2×21767869² = 947680241602322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21767839) 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, 10883934 + 10883935.

It is an arithmetic number, because the mean of its divisors is an integer number (10883935).

Almost surely, 2^21767869 is an apocalyptic number.

It is an amenable number.

21767869 is a deficient number, since it is larger than the sum of its proper divisors (1).

21767869 is an equidigital number, since it uses as much as digits as its factorization.

21767869 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 254016, while the sum is 46.

The square root of 21767869 is about 4665.6048911154. The cubic root of 21767869 is about 279.2149309686.

It can be divided in two parts, 217 and 67869, that added together give a palindrome (68086).

The spelling of 21767869 in words is "twenty-one million, seven hundred sixty-seven thousand, eight hundred sixty-nine".