651720911 has 4 divisors (see below), whose sum is σ = 651775824. Its totient is φ = 651666000.

The previous prime is 651720907. The next prime is 651720917. The reversal of 651720911 is 119027156.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 651720911 - 2² = 651720907 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (651720917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1430 + ... + 36131.

It is an arithmetic number, because the mean of its divisors is an integer number (162943956).

Almost surely, 2^651720911 is an apocalyptic number.

651720911 is a deficient number, since it is larger than the sum of its proper divisors (54913).

651720911 is a wasteful number, since it uses less digits than its factorization.

651720911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54912.

The product of its (nonzero) digits is 3780, while the sum is 32.

The square root of 651720911 is about 25528.8251002666. The cubic root of 651720911 is about 867.0029036734.

The spelling of 651720911 in words is "six hundred fifty-one million, seven hundred twenty thousand, nine hundred eleven".