651305491 has 4 divisors (see below), whose sum is σ = 651361984. Its totient is φ = 651249000.

The previous prime is 651305441. The next prime is 651305497. The reversal of 651305491 is 194503156.

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 3-Lehmer number, since φ(651305491) divides (651305491-1)³.

It is a cyclic number.

It is not a de Polignac number, because 651305491 - 2⁷ = 651305363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (651305497) 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, 4035 + ... + 36316.

It is an arithmetic number, because the mean of its divisors is an integer number (162840496).

Almost surely, 2^651305491 is an apocalyptic number.

651305491 is the 16141-st heptagonal number.

651305491 is a deficient number, since it is larger than the sum of its proper divisors (56493).

651305491 is a wasteful number, since it uses less digits than its factorization.

651305491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56492.

The product of its (nonzero) digits is 16200, while the sum is 34.

The square root of 651305491 is about 25520.6875103317. The cubic root of 651305491 is about 866.8186494966.

The spelling of 651305491 in words is "six hundred fifty-one million, three hundred five thousand, four hundred ninety-one".