1648640645 has 4 divisors (see below), whose sum is σ = 1978368780. Its totient is φ = 1318912512.

The previous prime is 1648640629. The next prime is 1648640681. The reversal of 1648640645 is 5460468461.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1273133761 + 375506884 = 35681^2 + 19378^2 .

It is a cyclic number.

It is not a de Polignac number, because 1648640645 - 2⁴ = 1648640629 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1648640596 and 1648640605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 164864060 + ... + 164864069.

It is an arithmetic number, because the mean of its divisors is an integer number (494592195).

Almost surely, 2^1648640645 is an apocalyptic number.

It is an amenable number.

1648640645 is a deficient number, since it is larger than the sum of its proper divisors (329728135).

1648640645 is an equidigital number, since it uses as much as digits as its factorization.

1648640645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329728134.

The product of its (nonzero) digits is 552960, while the sum is 44.

The square root of 1648640645 is about 40603.4560721129. The cubic root of 1648640645 is about 1181.3411556055.

The spelling of 1648640645 in words is "one billion, six hundred forty-eight million, six hundred forty thousand, six hundred forty-five".