645411021 has 8 divisors (see below), whose sum is σ = 861025344. Its totient is φ = 430035360.

The previous prime is 645410963. The next prime is 645411029. The reversal of 645411021 is 120114546.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 645411021 - 2⁶ = 645410957 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 645410982 and 645411000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645411029) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53256 + ... + 64241.

It is an arithmetic number, because the mean of its divisors is an integer number (107628168).

Almost surely, 2^645411021 is an apocalyptic number.

It is an amenable number.

645411021 is a deficient number, since it is larger than the sum of its proper divisors (215614323).

645411021 is a wasteful number, since it uses less digits than its factorization.

645411021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119331.

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 645411021 is about 25404.9408777112. The cubic root of 645411021 is about 864.1957490610.

Adding to 645411021 its reverse (120114546), we get a palindrome (765525567).

The spelling of 645411021 in words is "six hundred forty-five million, four hundred eleven thousand, twenty-one".