1640567897 has 4 divisors (see below), whose sum is σ = 1711896960. Its totient is φ = 1569238836.

The previous prime is 1640567879. The next prime is 1640567911. The reversal of 1640567897 is 7987650461.

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.

It is a cyclic number.

It is not a de Polignac number, because 1640567897 - 2¹⁸ = 1640305753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1640567807) 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, 35664497 + ... + 35664542.

It is an arithmetic number, because the mean of its divisors is an integer number (427974240).

Almost surely, 2^1640567897 is an apocalyptic number.

It is an amenable number.

1640567897 is a deficient number, since it is larger than the sum of its proper divisors (71329063).

1640567897 is an equidigital number, since it uses as much as digits as its factorization.

1640567897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71329062.

The product of its (nonzero) digits is 2540160, while the sum is 53.

The square root of 1640567897 is about 40503.9244641800. The cubic root of 1640567897 is about 1179.4098113913.

The spelling of 1640567897 in words is "one billion, six hundred forty million, five hundred sixty-seven thousand, eight hundred ninety-seven".