21134989 has 2 divisors, whose sum is σ = 21134990. Its totient is φ = 21134988.

The previous prime is 21134987. The next prime is 21135001. The reversal of 21134989 is 98943112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15093225 + 6041764 = 3885^2 + 2458^2 .

It is a cyclic number.

It is not a de Polignac number, because 21134989 - 2¹ = 21134987 is a prime.

Together with 21134987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21134983) 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, 10567494 + 10567495.

It is an arithmetic number, because the mean of its divisors is an integer number (10567495).

Almost surely, 2^21134989 is an apocalyptic number.

It is an amenable number.

21134989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21134989 is an equidigital number, since it uses as much as digits as its factorization.

21134989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 37.

The square root of 21134989 is about 4597.2806092298. The cubic root of 21134989 is about 276.4823053618.

The spelling of 21134989 in words is "twenty-one million, one hundred thirty-four thousand, nine hundred eighty-nine".