691964219 has 2 divisors, whose sum is σ = 691964220. Its totient is φ = 691964218.

The previous prime is 691964137. The next prime is 691964281. The reversal of 691964219 is 912469196.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 691964219 - 2⁸ = 691963963 is a prime.

It is a super-2 number, since 2×691964219² = 957628960752559922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (691961219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345982109 + 345982110.

It is an arithmetic number, because the mean of its divisors is an integer number (345982110).

Almost surely, 2^691964219 is an apocalyptic number.

691964219 is a deficient number, since it is larger than the sum of its proper divisors (1).

691964219 is an equidigital number, since it uses as much as digits as its factorization.

691964219 is an evil number, because the sum of its binary digits is even.

The product of its digits is 209952, while the sum is 47.

The square root of 691964219 is about 26305.2127723765. The cubic root of 691964219 is about 884.4932969301.

The spelling of 691964219 in words is "six hundred ninety-one million, nine hundred sixty-four thousand, two hundred nineteen".