694343209921 has 2 divisors, whose sum is σ = 694343209922. Its totient is φ = 694343209920.

The previous prime is 694343209909. The next prime is 694343209979. The reversal of 694343209921 is 129902343496.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 680029480321 + 14313729600 = 824639^2 + 119640^2 .

It is a cyclic number.

It is not a de Polignac number, because 694343209921 - 2⁷ = 694343209793 is a prime.

It is a super-2 number, since 2×694343209921² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (694343203921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 347171604960 + 347171604961.

It is an arithmetic number, because the mean of its divisors is an integer number (347171604961).

Almost surely, 2^694343209921 is an apocalyptic number.

It is an amenable number.

694343209921 is a deficient number, since it is larger than the sum of its proper divisors (1).

694343209921 is an equidigital number, since it uses as much as digits as its factorization.

694343209921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2519424, while the sum is 52.

The spelling of 694343209921 in words is "six hundred ninety-four billion, three hundred forty-three million, two hundred nine thousand, nine hundred twenty-one".