21210697 has 2 divisors, whose sum is σ = 21210698. Its totient is φ = 21210696.

The previous prime is 21210691. The next prime is 21210703. The reversal of 21210697 is 79601212.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (21210691) and next prime (21210703).

It can be written as a sum of positive squares in only one way, i.e., 15397776 + 5812921 = 3924^2 + 2411^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210697 - 2¹⁹ = 20686409 is a prime.

It is not a weakly prime, because it can be changed into another prime (21210691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605348 + 10605349.

It is an arithmetic number, because the mean of its divisors is an integer number (10605349).

Almost surely, 2^21210697 is an apocalyptic number.

It is an amenable number.

21210697 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210697 is an equidigital number, since it uses as much as digits as its factorization.

21210697 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 21210697 is about 4605.5072467645. The cubic root of 21210697 is about 276.8120425962.

The spelling of 21210697 in words is "twenty-one million, two hundred ten thousand, six hundred ninety-seven".