1640506423 has 4 divisors (see below), whose sum is σ = 1697075640. Its totient is φ = 1583937208.

The previous prime is 1640506397. The next prime is 1640506451. The reversal of 1640506423 is 3246050461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3246050461 = 281 ⋅11551781.

It is a cyclic number.

It is not a de Polignac number, because 1640506423 - 2¹⁷ = 1640375351 is a prime.

It is a super-2 number, since 2×1640506423² = 5382522647808509858, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640506463) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28284565 + ... + 28284622.

It is an arithmetic number, because the mean of its divisors is an integer number (424268910).

Almost surely, 2^1640506423 is an apocalyptic number.

1640506423 is a deficient number, since it is larger than the sum of its proper divisors (56569217).

1640506423 is an equidigital number, since it uses as much as digits as its factorization.

1640506423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56569216.

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 1640506423 is about 40503.1655923336. The cubic root of 1640506423 is about 1179.3950799184.

Adding to 1640506423 its reverse (3246050461), we get a palindrome (4886556884).

The spelling of 1640506423 in words is "one billion, six hundred forty million, five hundred six thousand, four hundred twenty-three".