1640690377 has 2 divisors, whose sum is σ = 1640690378. Its totient is φ = 1640690376.

The previous prime is 1640690369. The next prime is 1640690393. The reversal of 1640690377 is 7730960461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1182259456 + 458430921 = 34384^2 + 21411^2 .

It is a cyclic number.

It is not a de Polignac number, because 1640690377 - 2³ = 1640690369 is a prime.

It is not a weakly prime, because it can be changed into another prime (1640690477) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820345188 + 820345189.

It is an arithmetic number, because the mean of its divisors is an integer number (820345189).

Almost surely, 2^1640690377 is an apocalyptic number.

It is an amenable number.

1640690377 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640690377 is an equidigital number, since it uses as much as digits as its factorization.

1640690377 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 190512, while the sum is 43.

The square root of 1640690377 is about 40505.4363882183. The cubic root of 1640690377 is about 1179.4391610897.

The spelling of 1640690377 in words is "one billion, six hundred forty million, six hundred ninety thousand, three hundred seventy-seven".