66172551 has 8 divisors (see below), whose sum is σ = 93420144. Its totient is φ = 41520000.

The previous prime is 66172549. The next prime is 66172591. The reversal of 66172551 is 15527166.

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

It is not a de Polignac number, because 66172551 - 2¹ = 66172549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66172501) 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, 648700 + ... + 648801.

It is an arithmetic number, because the mean of its divisors is an integer number (11677518).

Almost surely, 2^66172551 is an apocalyptic number.

66172551 is a deficient number, since it is larger than the sum of its proper divisors (27247593).

66172551 is a wasteful number, since it uses less digits than its factorization.

66172551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1297521.

The product of its digits is 12600, while the sum is 33.

The square root of 66172551 is about 8134.6512525123. The cubic root of 66172551 is about 404.4758774131.

The spelling of 66172551 in words is "sixty-six million, one hundred seventy-two thousand, five hundred fifty-one".