51021506642445 has 24 divisors (see below), whose sum is σ = 90827474890776. Its totient is φ = 26476025067648.

The previous prime is 51021506642441. The next prime is 51021506642459. The reversal of 51021506642445 is 54424660512015.

51021506642445 is a `hidden beast` number, since 5 + 1 + 0 + 21 + 506 + 64 + 24 + 45 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 4846505384484 + 46175001257961 = 2201478^2 + 6795219^2 .

It is not a de Polignac number, because 51021506642445 - 2² = 51021506642441 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 51021506642445.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51021506642441) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15321772102 + ... + 15321775431.

It is an arithmetic number, because the mean of its divisors is an integer number (3784478120449).

Almost surely, 2^{51021506642445} is an apocalyptic number.

It is an amenable number.

51021506642445 is a deficient number, since it is larger than the sum of its proper divisors (39805968248331).

51021506642445 is a wasteful number, since it uses less digits than its factorization.

51021506642445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30643547581 (or 30643547578 counting only the distinct ones).

The product of its (nonzero) digits is 1152000, while the sum is 45.

The spelling of 51021506642445 in words is "fifty-one trillion, twenty-one billion, five hundred six million, six hundred forty-two thousand, four hundred forty-five".