651220261 has 8 divisors (see below), whose sum is σ = 667508184. Its totient is φ = 634951680.

The previous prime is 651220247. The next prime is 651220277. The reversal of 651220261 is 162022156.

It can be written as a sum of positive squares in 4 ways, for example, as 900 + 651219361 = 30^2 + 25519^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 651220261 - 2⁷ = 651220133 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 (651220211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82875 + ... + 90391.

It is an arithmetic number, because the mean of its divisors is an integer number (83438523).

Almost surely, 2^651220261 is an apocalyptic number.

It is an amenable number.

651220261 is a deficient number, since it is larger than the sum of its proper divisors (16287923).

651220261 is a wasteful number, since it uses less digits than its factorization.

651220261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9671.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 651220261 is about 25519.0176339137. The cubic root of 651220261 is about 866.7808371451.

The spelling of 651220261 in words is "six hundred fifty-one million, two hundred twenty thousand, two hundred sixty-one".