66651551 has 8 divisors (see below), whose sum is σ = 67473408. Its totient is φ = 65835000.

The previous prime is 66651547. The next prime is 66651553. The reversal of 66651551 is 15515666.

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

It is a cyclic number.

It is not a de Polignac number, because 66651551 - 2² = 66651547 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 (66651553) 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, 27686 + ... + 29996.

It is an arithmetic number, because the mean of its divisors is an integer number (8434176).

Almost surely, 2^66651551 is an apocalyptic number.

66651551 is a deficient number, since it is larger than the sum of its proper divisors (821857).

66651551 is a wasteful number, since it uses less digits than its factorization.

66651551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2653.

The product of its digits is 27000, while the sum is 35.

The square root of 66651551 is about 8164.0401150411. The cubic root of 66651551 is about 405.4494852091.

The spelling of 66651551 in words is "sixty-six million, six hundred fifty-one thousand, five hundred fifty-one".