66626551 has 4 divisors (see below), whose sum is σ = 66793104. Its totient is φ = 66460000.

The previous prime is 66626537. The next prime is 66626611. The reversal of 66626551 is 15562666.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66626551 - 2⁹ = 66626039 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66626551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66626531) 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, 82675 + ... + 83476.

It is an arithmetic number, because the mean of its divisors is an integer number (16698276).

Almost surely, 2^66626551 is an apocalyptic number.

66626551 is a deficient number, since it is larger than the sum of its proper divisors (166553).

66626551 is a wasteful number, since it uses less digits than its factorization.

66626551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166552.

The product of its digits is 64800, while the sum is 37.

The square root of 66626551 is about 8162.5088667639. The cubic root of 66626551 is about 405.3987861903.

The spelling of 66626551 in words is "sixty-six million, six hundred twenty-six thousand, five hundred fifty-one".