210640069 has 2 divisors, whose sum is σ = 210640070. Its totient is φ = 210640068.

The previous prime is 210640051. The next prime is 210640091. The reversal of 210640069 is 960046012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 168220900 + 42419169 = 12970^2 + 6513^2 .

It is a cyclic number.

It is not a de Polignac number, because 210640069 - 2¹⁵ = 210607301 is a prime.

It is a super-2 number, since 2×210640069² = 88738477336649522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (210640039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105320034 + 105320035.

It is an arithmetic number, because the mean of its divisors is an integer number (105320035).

Almost surely, 2^210640069 is an apocalyptic number.

It is an amenable number.

210640069 is a deficient number, since it is larger than the sum of its proper divisors (1).

210640069 is an equidigital number, since it uses as much as digits as its factorization.

210640069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 210640069 is about 14513.4444223279. Note that the first 4 decimals coincide. The cubic root of 210640069 is about 594.9954748614.

The spelling of 210640069 in words is "two hundred ten million, six hundred forty thousand, sixty-nine".