1640201609 has 4 divisors (see below), whose sum is σ = 1655530704. Its totient is φ = 1624872516.

The previous prime is 1640201587. The next prime is 1640201621. The reversal of 1640201609 is 9061020461.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9061020461 = 401 ⋅22596061.

It is a cyclic number.

It is not a de Polignac number, because 1640201609 - 2²⁴ = 1623424393 is a prime.

It is a super-2 number, since 2×1640201609² = 5380522636332377762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1640201669) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7664387 + ... + 7664600.

It is an arithmetic number, because the mean of its divisors is an integer number (413882676).

Almost surely, 2^1640201609 is an apocalyptic number.

It is an amenable number.

1640201609 is a deficient number, since it is larger than the sum of its proper divisors (15329095).

1640201609 is a wasteful number, since it uses less digits than its factorization.

1640201609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15329094.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 1640201609 is about 40499.4025758405. The cubic root of 1640201609 is about 1179.3220296305.

The spelling of 1640201609 in words is "one billion, six hundred forty million, two hundred one thousand, six hundred nine".