645473615 has 4 divisors (see below), whose sum is σ = 774568344. Its totient is φ = 516378888.

The previous prime is 645473611. The next prime is 645473617. The reversal of 645473615 is 516374546.

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

It is a cyclic number.

It is not a de Polignac number, because 645473615 - 2² = 645473611 is a prime.

It is a super-2 number, since 2×645473615² = 833272375322336450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645473611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64547357 + ... + 64547366.

It is an arithmetic number, because the mean of its divisors is an integer number (193642086).

Almost surely, 2^645473615 is an apocalyptic number.

645473615 is a deficient number, since it is larger than the sum of its proper divisors (129094729).

645473615 is a wasteful number, since it uses less digits than its factorization.

645473615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129094728.

The product of its digits is 302400, while the sum is 41.

The square root of 645473615 is about 25406.1727735604. The cubic root of 645473615 is about 864.2236856359.

The spelling of 645473615 in words is "six hundred forty-five million, four hundred seventy-three thousand, six hundred fifteen".