1640471639 has 2 divisors, whose sum is σ = 1640471640. Its totient is φ = 1640471638.

The previous prime is 1640471621. The next prime is 1640471641. The reversal of 1640471639 is 9361740461.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1640471639 is a prime.

It is a super-2 number, since 2×1640471639² = 5382294396726692642, which contains 22 as substring.

Together with 1640471641, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 1640471596 and 1640471605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1640471659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820235819 + 820235820.

It is an arithmetic number, because the mean of its divisors is an integer number (820235820).

Almost surely, 2^1640471639 is an apocalyptic number.

1640471639 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640471639 is an equidigital number, since it uses as much as digits as its factorization.

1640471639 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108864, while the sum is 41.

The square root of 1640471639 is about 40502.7361915217. The cubic root of 1640471639 is about 1179.3867442062.

The spelling of 1640471639 in words is "one billion, six hundred forty million, four hundred seventy-one thousand, six hundred thirty-nine".