1640690369 has 2 divisors, whose sum is σ = 1640690370. Its totient is φ = 1640690368.

The previous prime is 1640690353. The next prime is 1640690377. The reversal of 1640690369 is 9630960461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1640655025 + 35344 = 40505^2 + 188^2 .

It is a cyclic number.

It is not a de Polignac number, because 1640690369 - 2⁴ = 1640690353 is a prime.

It is a super-2 number, since 2×1640690369² = 5383729773858712322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1640690309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820345184 + 820345185.

It is an arithmetic number, because the mean of its divisors is an integer number (820345185).

Almost surely, 2^1640690369 is an apocalyptic number.

It is an amenable number.

1640690369 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640690369 is an equidigital number, since it uses as much as digits as its factorization.

1640690369 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 209952, while the sum is 44.

The square root of 1640690369 is about 40505.4362894661. The cubic root of 1640690369 is about 1179.4391591727.

The spelling of 1640690369 in words is "one billion, six hundred forty million, six hundred ninety thousand, three hundred sixty-nine".