210697947809 has 2 divisors, whose sum is σ = 210697947810. Its totient is φ = 210697947808.

The previous prime is 210697947709. The next prime is 210697947829. The reversal of 210697947809 is 908749796012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 200274150400 + 10423797409 = 447520^2 + 102097^2 .

It is a cyclic number.

It is not a de Polignac number, because 210697947809 - 2⁸ = 210697947553 is a prime.

It is not a weakly prime, because it can be changed into another prime (210697947829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105348973904 + 105348973905.

It is an arithmetic number, because the mean of its divisors is an integer number (105348973905).

Almost surely, 2^210697947809 is an apocalyptic number.

It is an amenable number.

210697947809 is a deficient number, since it is larger than the sum of its proper divisors (1).

210697947809 is an equidigital number, since it uses as much as digits as its factorization.

210697947809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13716864, while the sum is 62.

The spelling of 210697947809 in words is "two hundred ten billion, six hundred ninety-seven million, nine hundred forty-seven thousand, eight hundred nine".