1640209531 has 2 divisors, whose sum is σ = 1640209532. Its totient is φ = 1640209530.

The previous prime is 1640209517. The next prime is 1640209537. The reversal of 1640209531 is 1359020461.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1640209531 - 2¹⁵ = 1640176763 is a prime.

It is a super-2 number, since 2×1640209531² = 5380574611166479922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1640209493 and 1640209502.

It is not a weakly prime, because it can be changed into another prime (1640209537) 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, 820104765 + 820104766.

It is an arithmetic number, because the mean of its divisors is an integer number (820104766).

Almost surely, 2^1640209531 is an apocalyptic number.

1640209531 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640209531 is an equidigital number, since it uses as much as digits as its factorization.

1640209531 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 1640209531 is about 40499.5003796343. The cubic root of 1640209531 is about 1179.3239282943.

Adding to 1640209531 its reverse (1359020461), we get a palindrome (2999229992).

The spelling of 1640209531 in words is "one billion, six hundred forty million, two hundred nine thousand, five hundred thirty-one".