1649394805 has 4 divisors (see below), whose sum is σ = 1979273772. Its totient is φ = 1319515840.

The previous prime is 1649394787. The next prime is 1649394833. The reversal of 1649394805 is 5084939461.

It is a happy number.

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 655001649 + 994393156 = 25593^2 + 31534^2 .

It is not a de Polignac number, because 1649394805 - 2¹¹ = 1649392757 is a prime.

It is a Duffinian number.

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, 164939476 + ... + 164939485.

It is an arithmetic number, because the mean of its divisors is an integer number (494818443).

Almost surely, 2^1649394805 is an apocalyptic number.

It is an amenable number.

1649394805 is a deficient number, since it is larger than the sum of its proper divisors (329878967).

1649394805 is an equidigital number, since it uses as much as digits as its factorization.

1649394805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329878966.

The product of its (nonzero) digits is 933120, while the sum is 49.

The square root of 1649394805 is about 40612.7419044812. The cubic root of 1649394805 is about 1181.5212604361.

It can be divided in two parts, 164939 and 4805, that added together give a square (169744 = 412²).

The spelling of 1649394805 in words is "one billion, six hundred forty-nine million, three hundred ninety-four thousand, eight hundred five".