21143879 has 2 divisors, whose sum is σ = 21143880. Its totient is φ = 21143878.

The previous prime is 21143867. The next prime is 21143893. The reversal of 21143879 is 97834112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21143879 - 2⁸ = 21143623 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21143839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10571939 + 10571940.

It is an arithmetic number, because the mean of its divisors is an integer number (10571940).

Almost surely, 2^21143879 is an apocalyptic number.

21143879 is a deficient number, since it is larger than the sum of its proper divisors (1).

21143879 is an equidigital number, since it uses as much as digits as its factorization.

21143879 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 35.

The square root of 21143879 is about 4598.2473835147. The cubic root of 21143879 is about 276.5210654663.

It can be divided in two parts, 21143 and 879, that added together give a palindrome (22022).

The spelling of 21143879 in words is "twenty-one million, one hundred forty-three thousand, eight hundred seventy-nine".