651556122661 has 4 divisors (see below), whose sum is σ = 659406196512. Its totient is φ = 643706048812.

The previous prime is 651556122653. The next prime is 651556122673. The reversal of 651556122661 is 166221655156.

It is a happy number.

651556122661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 not a de Polignac number, because 651556122661 - 2³ = 651556122653 is a prime.

It is a super-3 number, since 3×651556122661³ (a number of 36 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (651556123661) 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, 3925036801 + ... + 3925036966.

It is an arithmetic number, because the mean of its divisors is an integer number (164851549128).

Almost surely, 2^651556122661 is an apocalyptic number.

It is an amenable number.

651556122661 is a deficient number, since it is larger than the sum of its proper divisors (7850073851).

651556122661 is an equidigital number, since it uses as much as digits as its factorization.

651556122661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7850073850.

The product of its digits is 648000, while the sum is 46.

It can be divided in two parts, 65155 and 6122661, that added together give a palindrome (6187816).

The spelling of 651556122661 in words is "six hundred fifty-one billion, five hundred fifty-six million, one hundred twenty-two thousand, six hundred sixty-one".