650641721 has 4 divisors (see below), whose sum is σ = 654633552. Its totient is φ = 646649892.

The previous prime is 650641711. The next prime is 650641741. The reversal of 650641721 is 127146056.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 650641721 - 2²⁶ = 583532857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (650641711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1995671 + ... + 1995996.

It is an arithmetic number, because the mean of its divisors is an integer number (163658388).

Almost surely, 2^650641721 is an apocalyptic number.

It is an amenable number.

650641721 is a deficient number, since it is larger than the sum of its proper divisors (3991831).

650641721 is a wasteful number, since it uses less digits than its factorization.

650641721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3991830.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 650641721 is about 25507.6796475101. The cubic root of 650641721 is about 866.5240802079.

Adding to 650641721 its reverse (127146056), we get a palindrome (777787777).

The spelling of 650641721 in words is "six hundred fifty million, six hundred forty-one thousand, seven hundred twenty-one".