1646561425 has 6 divisors (see below), whose sum is σ = 2041736198. Its totient is φ = 1317249120.

The previous prime is 1646561419. The next prime is 1646561429. The reversal of 1646561425 is 5241656461.

It can be written as a sum of positive squares in 3 ways, for example, as 46881409 + 1599680016 = 6847^2 + 39996^2 .

It is not a de Polignac number, because 1646561425 - 2³ = 1646561417 is a prime.

It is a super-2 number, since 2×1646561425² = 5422329052596061250, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1646561429) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 32931204 + ... + 32931253.

Almost surely, 2^1646561425 is an apocalyptic number.

It is an amenable number.

1646561425 is a deficient number, since it is larger than the sum of its proper divisors (395174773).

1646561425 is an equidigital number, since it uses as much as digits as its factorization.

1646561425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65862467 (or 65862462 counting only the distinct ones).

The product of its digits is 172800, while the sum is 40.

The square root of 1646561425 is about 40577.8440161623. The cubic root of 1646561425 is about 1180.8443217480.

The spelling of 1646561425 in words is "one billion, six hundred forty-six million, five hundred sixty-one thousand, four hundred twenty-five".