21063997 has 2 divisors, whose sum is σ = 21063998. Its totient is φ = 21063996.

The previous prime is 21063983. The next prime is 21064009. The reversal of 21063997 is 79936012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20169081 + 894916 = 4491^2 + 946^2 .

It is a cyclic number.

It is not a de Polignac number, because 21063997 - 2⁷ = 21063869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21063907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10531998 + 10531999.

It is an arithmetic number, because the mean of its divisors is an integer number (10531999).

Almost surely, 2^21063997 is an apocalyptic number.

It is an amenable number.

21063997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21063997 is an equidigital number, since it uses as much as digits as its factorization.

21063997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20412, while the sum is 37.

The square root of 21063997 is about 4589.5530283460. The cubic root of 21063997 is about 276.1723919500.

The spelling of 21063997 in words is "twenty-one million, sixty-three thousand, nine hundred ninety-seven".