6720645 has 32 divisors (see below), whose sum is σ = 11289600. Its totient is φ = 3409920.

The previous prime is 6720629. The next prime is 6720667. The reversal of 6720645 is 5460276.

6720645 = 81² + 82² + ... + 274².

It is not a de Polignac number, because 6720645 - 2⁴ = 6720629 is a prime.

It is an Ulam number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 45031 + ... + 45179.

It is an arithmetic number, because the mean of its divisors is an integer number (352800).

Almost surely, 2^6720645 is an apocalyptic number.

It is an amenable number.

6720645 is a deficient number, since it is larger than the sum of its proper divisors (4568955).

6720645 is a wasteful number, since it uses less digits than its factorization.

6720645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285.

The product of its (nonzero) digits is 10080, while the sum is 30.

The square root of 6720645 is about 2592.4206834540. The cubic root of 6720645 is about 188.7137965445.

The spelling of 6720645 in words is "six million, seven hundred twenty thousand, six hundred forty-five".