694940209 has 2 divisors, whose sum is σ = 694940210. Its totient is φ = 694940208.

The previous prime is 694940153. The next prime is 694940227. The reversal of 694940209 is 902049496.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 626000400 + 68939809 = 25020^2 + 8303^2 .

It is a cyclic number.

It is not a de Polignac number, because 694940209 - 2¹⁹ = 694415921 is a prime.

It is not a weakly prime, because it can be changed into another prime (694940809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 347470104 + 347470105.

It is an arithmetic number, because the mean of its divisors is an integer number (347470105).

Almost surely, 2^694940209 is an apocalyptic number.

It is an amenable number.

694940209 is a deficient number, since it is larger than the sum of its proper divisors (1).

694940209 is an equidigital number, since it uses as much as digits as its factorization.

694940209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 139968, while the sum is 43.

The square root of 694940209 is about 26361.7186275857. The cubic root of 694940209 is about 885.7594889062.

The spelling of 694940209 in words is "six hundred ninety-four million, nine hundred forty thousand, two hundred nine".