21084377 has 2 divisors, whose sum is σ = 21084378. Its totient is φ = 21084376.

The previous prime is 21084317. The next prime is 21084379. The reversal of 21084377 is 77348012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20106256 + 978121 = 4484^2 + 989^2 .

It is a cyclic number.

It is not a de Polignac number, because 21084377 - 2⁶ = 21084313 is a prime.

Together with 21084379, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21084379) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10542188 + 10542189.

It is an arithmetic number, because the mean of its divisors is an integer number (10542189).

Almost surely, 2^21084377 is an apocalyptic number.

It is an amenable number.

21084377 is a deficient number, since it is larger than the sum of its proper divisors (1).

21084377 is an equidigital number, since it uses as much as digits as its factorization.

21084377 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9408, while the sum is 32.

The square root of 21084377 is about 4591.7727513456. The cubic root of 21084377 is about 276.2614313841.

The spelling of 21084377 in words is "twenty-one million, eighty-four thousand, three hundred seventy-seven".