649217641 has 4 divisors (see below), whose sum is σ = 687406932. Its totient is φ = 611028352.

The previous prime is 649217633. The next prime is 649217659. The reversal of 649217641 is 146712946.

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

It can be written as a sum of positive squares in 2 ways, for example, as 219899241 + 429318400 = 14829^2 + 20720^2 .

It is a cyclic number.

It is not a de Polignac number, because 649217641 - 2³ = 649217633 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 649217594 and 649217603.

It is not an unprimeable number, because it can be changed into a prime (649217141) 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, 19094620 + ... + 19094653.

It is an arithmetic number, because the mean of its divisors is an integer number (171851733).

Almost surely, 2^649217641 is an apocalyptic number.

It is an amenable number.

649217641 is a deficient number, since it is larger than the sum of its proper divisors (38189291).

649217641 is a wasteful number, since it uses less digits than its factorization.

649217641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38189290.

The product of its digits is 72576, while the sum is 40.

The square root of 649217641 is about 25479.7496259284. The cubic root of 649217641 is about 865.8914222404.

The spelling of 649217641 in words is "six hundred forty-nine million, two hundred seventeen thousand, six hundred forty-one".