1646611409 has 2 divisors, whose sum is σ = 1646611410. Its totient is φ = 1646611408.

The previous prime is 1646611403. The next prime is 1646611429. The reversal of 1646611409 is 9041166461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1147312384 + 499299025 = 33872^2 + 22345^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1646611409 is a prime.

It is a super-2 number, since 2×1646611409² = 5422658264497930562, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1646611403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 823305704 + 823305705.

It is an arithmetic number, because the mean of its divisors is an integer number (823305705).

Almost surely, 2^1646611409 is an apocalyptic number.

It is an amenable number.

1646611409 is a deficient number, since it is larger than the sum of its proper divisors (1).

1646611409 is an equidigital number, since it uses as much as digits as its factorization.

1646611409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 1646611409 is about 40578.4599140973. The cubic root of 1646611409 is about 1180.8562704318.

The spelling of 1646611409 in words is "one billion, six hundred forty-six million, six hundred eleven thousand, four hundred nine".