645213754 has 4 divisors (see below), whose sum is σ = 967820634. Its totient is φ = 322606876.

The previous prime is 645213743. The next prime is 645213773. The reversal of 645213754 is 457312546.

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

It can be written as a sum of positive squares in only one way, i.e., 632774025 + 12439729 = 25155^2 + 3527^2 .

It is a super-3 number, since 3×645213754³ (a number of 27 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161303437 + ... + 161303440.

Almost surely, 2^645213754 is an apocalyptic number.

645213754 is a deficient number, since it is larger than the sum of its proper divisors (322606880).

645213754 is a wasteful number, since it uses less digits than its factorization.

645213754 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322606879.

The product of its digits is 100800, while the sum is 37.

The square root of 645213754 is about 25401.0581275663. The cubic root of 645213754 is about 864.1076942304.

The spelling of 645213754 in words is "six hundred forty-five million, two hundred thirteen thousand, seven hundred fifty-four".