1645513966 has 4 divisors (see below), whose sum is σ = 2468270952. Its totient is φ = 822756982.

The previous prime is 1645513931. The next prime is 1645513973. The reversal of 1645513966 is 6693155461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6693155461 = 47 ⋅142407563.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 411378490 + ... + 411378493.

It is an arithmetic number, because the mean of its divisors is an integer number (617067738).

Almost surely, 2^1645513966 is an apocalyptic number.

1645513966 is a deficient number, since it is larger than the sum of its proper divisors (822756986).

1645513966 is an equidigital number, since it uses as much as digits as its factorization.

1645513966 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 822756985.

The product of its digits is 583200, while the sum is 46.

The square root of 1645513966 is about 40564.9351780574. The cubic root of 1645513966 is about 1180.5938708451.

The spelling of 1645513966 in words is "one billion, six hundred forty-five million, five hundred thirteen thousand, nine hundred sixty-six".