21140689 has 2 divisors, whose sum is σ = 21140690. Its totient is φ = 21140688.

The previous prime is 21140683. The next prime is 21140699. The reversal of 21140689 is 98604112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13395600 + 7745089 = 3660^2 + 2783^2 .

It is a cyclic number.

It is not a de Polignac number, because 21140689 - 2¹³ = 21132497 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21140689.

It is not a weakly prime, because it can be changed into another prime (21140683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10570344 + 10570345.

It is an arithmetic number, because the mean of its divisors is an integer number (10570345).

Almost surely, 2^21140689 is an apocalyptic number.

It is an amenable number.

21140689 is a deficient number, since it is larger than the sum of its proper divisors (1).

21140689 is an equidigital number, since it uses as much as digits as its factorization.

21140689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 21140689 is about 4597.9004991409. The cubic root of 21140689 is about 276.5071584224.

The spelling of 21140689 in words is "twenty-one million, one hundred forty thousand, six hundred eighty-nine".