66654551 has 4 divisors (see below), whose sum is σ = 66751704. Its totient is φ = 66557400.

The previous prime is 66654547. The next prime is 66654559. The reversal of 66654551 is 15545666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15545666 = 2 ⋅7772833.

It is a cyclic number.

It is not a de Polignac number, because 66654551 - 2² = 66654547 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 (66654559) 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, 47540 + ... + 48921.

It is an arithmetic number, because the mean of its divisors is an integer number (16687926).

Almost surely, 2^66654551 is an apocalyptic number.

66654551 is a deficient number, since it is larger than the sum of its proper divisors (97153).

66654551 is an equidigital number, since it uses as much as digits as its factorization.

66654551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97152.

The product of its digits is 108000, while the sum is 38.

The square root of 66654551 is about 8164.2238455349. The cubic root of 66654551 is about 405.4555682394.

The spelling of 66654551 in words is "sixty-six million, six hundred fifty-four thousand, five hundred fifty-one".