66515001551 has 4 divisors (see below), whose sum is σ = 68137318704. Its totient is φ = 64892684400.

The previous prime is 66515001517. The next prime is 66515001569. The reversal of 66515001551 is 15510051566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15510051566 = 2 ⋅7755025783.

It is not a de Polignac number, because 66515001551 - 2²² = 66510807247 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 (66515001571) 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, 811158515 + ... + 811158596.

It is an arithmetic number, because the mean of its divisors is an integer number (17034329676).

Almost surely, 2^66515001551 is an apocalyptic number.

66515001551 is a deficient number, since it is larger than the sum of its proper divisors (1622317153).

66515001551 is a wasteful number, since it uses less digits than its factorization.

66515001551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1622317152.

The product of its (nonzero) digits is 22500, while the sum is 35.

The spelling of 66515001551 in words is "sixty-six billion, five hundred fifteen million, one thousand, five hundred fifty-one".