651721499 has 16 divisors (see below), whose sum is σ = 778221024. Its totient is φ = 537926400.

The previous prime is 651721471. The next prime is 651721513. The reversal of 651721499 is 994127156.

It is not a de Polignac number, because 651721499 - 2²⁰ = 650672923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (651721799) 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 15 ways as a sum of consecutive naturals, for example, 28634 + ... + 46079.

It is an arithmetic number, because the mean of its divisors is an integer number (48638814).

Almost surely, 2^651721499 is an apocalyptic number.

651721499 is a deficient number, since it is larger than the sum of its proper divisors (126499525).

651721499 is a wasteful number, since it uses less digits than its factorization.

651721499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74798.

The product of its digits is 136080, while the sum is 44.

The square root of 651721499 is about 25528.8366166576. The cubic root of 651721499 is about 867.0031644177.

The spelling of 651721499 in words is "six hundred fifty-one million, seven hundred twenty-one thousand, four hundred ninety-nine".