1640531 has 2 divisors, whose sum is σ = 1640532. Its totient is φ = 1640530.

The previous prime is 1640519. The next prime is 1640539. The reversal of 1640531 is 1350461.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1640531 - 2⁶ = 1640467 is a prime.

It is a super-2 number, since 2×1640531² = 5382683923922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (1640539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820265 + 820266.

It is an arithmetic number, because the mean of its divisors is an integer number (820266).

2^1640531 is an apocalyptic number.

1640531 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640531 is an equidigital number, since it uses as much as digits as its factorization.

1640531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 1640531 is about 1280.8321513766. The cubic root of 1640531 is about 117.9400969532.

Adding to 1640531 its reverse (1350461), we get a palindrome (2990992).

The spelling of 1640531 in words is "one million, six hundred forty thousand, five hundred thirty-one".