21053897 has 2 divisors, whose sum is σ = 21053898. Its totient is φ = 21053896.

The previous prime is 21053887. The next prime is 21053909. The reversal of 21053897 is 79835012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18800896 + 2253001 = 4336^2 + 1501^2 .

It is a cyclic number.

It is not a de Polignac number, because 21053897 - 2⁶ = 21053833 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21053887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10526948 + 10526949.

It is an arithmetic number, because the mean of its divisors is an integer number (10526949).

Almost surely, 2^21053897 is an apocalyptic number.

It is an amenable number.

21053897 is a deficient number, since it is larger than the sum of its proper divisors (1).

21053897 is an equidigital number, since it uses as much as digits as its factorization.

21053897 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 21053897 is about 4588.4525714014. The cubic root of 21053897 is about 276.1282441545.

The spelling of 21053897 in words is "twenty-one million, fifty-three thousand, eight hundred ninety-seven".