651778081 has 4 divisors (see below), whose sum is σ = 653656752. Its totient is φ = 649899412.

The previous prime is 651778073. The next prime is 651778151. The reversal of 651778081 is 180877156.

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 651778081 - 2³ = 651778073 is a prime.

It is a super-2 number, since 2×651778081² = 849629333744085122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (651772081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 938815 + ... + 939508.

It is an arithmetic number, because the mean of its divisors is an integer number (163414188).

Almost surely, 2^651778081 is an apocalyptic number.

It is an amenable number.

651778081 is a deficient number, since it is larger than the sum of its proper divisors (1878671).

651778081 is a wasteful number, since it uses less digits than its factorization.

651778081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1878670.

The product of its (nonzero) digits is 94080, while the sum is 43.

The square root of 651778081 is about 25529.9447903829. The cubic root of 651778081 is about 867.0282545590.

The spelling of 651778081 in words is "six hundred fifty-one million, seven hundred seventy-eight thousand, eighty-one".