1640623 has 2 divisors, whose sum is σ = 1640624. Its totient is φ = 1640622.

The previous prime is 1640621. The next prime is 1640633. The reversal of 1640623 is 3260461.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1640623 - 2¹ = 1640621 is a prime.

Together with 1640621, it forms a pair of twin primes.

It is a plaindrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 1640594 and 1640603.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1640621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820311 + 820312.

It is an arithmetic number, because the mean of its divisors is an integer number (820312).

2^1640623 is an apocalyptic number.

1640623 is a deficient number, since it is larger than the sum of its proper divisors (1).

1640623 is an equidigital number, since it uses as much as digits as its factorization.

1640623 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 1640623 is about 1280.8680650247. The cubic root of 1640623 is about 117.9423015821.

The spelling of 1640623 in words is "one million, six hundred forty thousand, six hundred twenty-three".