51501005661 has 8 divisors (see below), whose sum is σ = 78477722944. Its totient is φ = 29429146080.

The previous prime is 51501005629. The next prime is 51501005681. The reversal of 51501005661 is 16650010515.

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

It is not a de Polignac number, because 51501005661 - 2⁵ = 51501005629 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 (51501005681) 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, 1226214400 + ... + 1226214441.

It is an arithmetic number, because the mean of its divisors is an integer number (9809715368).

Almost surely, 2^51501005661 is an apocalyptic number.

It is an amenable number.

51501005661 is a deficient number, since it is larger than the sum of its proper divisors (26976717283).

51501005661 is a wasteful number, since it uses less digits than its factorization.

51501005661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2452428851.

The product of its (nonzero) digits is 4500, while the sum is 30.

The spelling of 51501005661 in words is "fifty-one billion, five hundred one million, five thousand, six hundred sixty-one".